Mia kolegino alportas ĉiujn dosierojn, por ke ni povu komenci la kunvenon ĝustatempe.

Because mia kolegino is the subject of the sentence: the person doing the action.

In Esperanto, the -n ending is usually used for the direct object, not the subject.

• Mia kolegino alportas... = My colleague brings...
• The colleague is doing the bringing, so no -n.

If she were the object, then you would use -n:

• Mi vidas mian koleginon. = I see my colleague.

Also, kolegino specifically means a female colleague. The base form is kolego.

The suffix -in- marks the feminine form.

So:

• kolego = colleague
• kolegino = female colleague

This is very common in Esperanto:

• patro = father / parent in some contexts
• patrino = mother
• frato = brother
• fratino = sister

So mia kolegino means specifically my female colleague.

The prefix al- often adds the idea of movement toward someone or something.

• porti = to carry, to wear, to transport
• alporti = to bring, to carry to a place

So:

• Ŝi portas la dosierojn. = She is carrying the files.
• Ŝi alportas la dosierojn. = She brings the files / carries the files here.

In this sentence, alportas suggests bringing the files to the place where we can begin the meeting.

Because ĉiujn dosierojn is the direct object, and in Esperanto words that go together agree with each other.

• dosierojn has -n because it is the object.
• ĉiujn also takes -n because it describes dosierojn.

So Esperanto shows agreement in case and number:

• ĉiu dosiero = each file
• ĉiuj dosieroj = all the files
• ĉiujn dosierojn = all the files (as object)

This same pattern happens with adjectives too:

• la ruĝaj libroj
• mi vidas la ruĝajn librojn

Because the sentence refers to all the files, plural, not each file singular.

Compare:

• ĉiun dosieron = each file / every file
• ĉiujn dosierojn = all the files

So the difference is both meaning and number:

• ĉiun
  • singular noun
• ĉiujn
  • plural noun

In this sentence, the idea is that she brings the whole set of files.

Esperanto uses la a bit more simply than English, but it still depends on how specific the noun is.

In ĉiujn dosierojn, the word ĉiujn already makes the noun phrase quite definite in sense, so la is often unnecessary.

• ĉiujn dosierojn = all the files

In la kunvenon, the speaker is referring to a specific meeting, so la is natural:

• la kunvenon = the meeting

You could sometimes see ĉiujn la dosierojn in some contexts, but ĉiujn dosierojn is the more normal, simple phrasing here.

Por ke means so that or in order that and introduces a clause with its own subject and verb.

Here:

• por ke ni povu komenci la kunvenon ĝustatempe
• = so that we can start the meeting on time

This is different from plain por, which is followed by an infinitive when the subject stays effectively the same or when no separate finite clause is needed.

Compare:

• Mi venis por helpi. = I came to help.
• Mi venis, por ke vi ne estu sola. = I came so that you would not be alone.

In your sentence, there is a full clause after it: ni povu komenci..., so por ke is the correct choice.

Because after por ke, Esperanto normally uses the -u verb form.

The -u form is often called the volitive. It is used for ideas like intention, purpose, wish, command, or desired result.

So:

• ni povas = we can
• ni povu = so that we may/can, with a sense of purpose or intended possibility

In this sentence:

• por ke ni povu komenci...
• literally something like so that we may be able to begin...

English usually just says so that we can begin, but Esperanto uses povu because the clause is expressing purpose, not a plain statement of fact.

In a sentence like this, povu is best understood as part of the purpose structure after por ke. English can translate it in several ways depending on style:

• so that we can start
• so that we may start
• so that we’ll be able to start

The key point is not one exact English modal verb. The important thing is that povu is the -u form of povi and is used because the clause expresses purpose.

So do not think of it as exactly equal to just one English word. In context, it means the bringing of the files makes it possible for us to begin the meeting.

Because it follows povu.

In Esperanto, modal-type verbs such as povi are followed by an infinitive:

• Mi povas veni. = I can come.
• Ni povu komenci. = so that we can begin

So:

• povu = may be able / can
• komenci = to begin

This is similar to English can begin rather than can begins.

Because la kunvenon is the direct object of komenci.

• komenci ion = to begin something
• Here, the thing being begun is the meeting

So:

• la kunveno = the meeting
• la kunvenon = the meeting, as object

This gives the structure:

• ni povu komenci la kunvenon
• we can begin the meeting

Ĝustatempe means on time, at the right time, or punctually, depending on context.

It is built from:

• ĝusta = correct, exact, proper
• tempo = time
• -e = adverb ending

So the idea is something like at the proper time.

Esperanto often forms adverbs this way:

• rapida → rapide = quickly
• bona → bone = well

But ĝustatempe is a more compact built-up expression meaning in a timely / punctual way.

Yes, in many contexts akurate could also work, because it can mean accurately or punctually, depending on context.

But there is a slight difference in feel:

• ĝustatempe = at the right time, on time
• akurate = punctually, exactly, with precision

For starting a meeting, ĝustatempe sounds very natural because the focus is on starting at the proper time.

Not completely. Esperanto word order is fairly flexible because endings show the grammatical roles.

The standard order here is very natural:

• Mia kolegino alportas ĉiujn dosierojn, por ke ni povu komenci la kunvenon ĝustatempe.

But some rearrangement is possible for emphasis, for example:

• Ĉiujn dosierojn mia kolegino alportas...
• Por ke ni povu komenci la kunvenon ĝustatempe, mia kolegino alportas ĉiujn dosierojn.

Even with a different order, the -n endings still show what the objects are.

That said, the original version is the clearest and most neutral.

You can divide it into two main parts:

1. Main clause:

   • Mia kolegino alportas ĉiujn dosierojn
   • My female colleague brings all the files

2. Purpose clause:

   • por ke ni povu komenci la kunvenon ĝustatempe
   • so that we can begin the meeting on time

So the full structure is:

• someone does an action
• for a purpose

A very useful pattern to remember is:

• [main clause], por ke [subject] [verb in -u form] ...

For example:

• Mi klarigas ĉion, por ke vi komprenu.
• I explain everything so that you understand.

Your sentence follows exactly that pattern.