Mia tablo denove fariĝis senorda, ĉar mi lasis sur ĝi librojn, biletojn kaj la pasporton.

Fariĝis is the past-tense form of fariĝi, which means to become.

So:

• fariĝi = to become
• fariĝas = becomes / is becoming
• fariĝis = became

In this sentence, Mia tablo denove fariĝis senorda means that the table became messy again.

A useful contrast:

• Mi faris la tablon senorda would mean I made the table messy
• La tablo fariĝis senorda means the table became messy

So fariĝi describes a change of state.

Because senorda is not a direct object. It is a predicate adjective describing the state that the table became.

In La tablo fariĝis senorda:

• la tablo = the subject
• fariĝis = became
• senorda = messy / untidy

The adjective simply describes the subject, so it does not take -n.

Compare:

• Mi vidas senordan tablon = I see a messy table
  Here senordan describes tablon, which is a direct object, so it gets -n.

But:

• La tablo fariĝis senorda = The table became messy
  No direct object here.

Denove means again.

In this sentence, it modifies fariĝis:

• Mia tablo denove fariĝis senorda = My table became messy again

Esperanto word order is fairly flexible, so you could also see:

• Denove mia tablo fariĝis senorda
• Mia tablo fariĝis denove senorda

The version in the sentence is very natural.

Ĉar means because. It introduces the reason:

• Mia tablo denove fariĝis senorda, ĉar...
  = My table became messy again, because...

So the second clause explains why the table became messy:

• ĉar mi lasis sur ĝi librojn, biletojn kaj la pasporton
  = because I left books, notes/tickets, and the passport on it

Here lasis means left in the sense of left something somewhere.

• lasi = to leave, to let
• lasis = left / let

In this sentence:

• mi lasis sur ĝi librojn... = I left books on it

Esperanto lasi can also mean to let / allow, depending on context:

• Mi lasis lin iri. = I let him go.

So yes, lasi can mean both leave and let, and the context tells you which meaning is intended.

Because this is location, not motion toward.

• sur ĝi = on it
• sur ĝin = onto it

In the sentence, the books and other items are simply resting on the table, so Esperanto uses sur ĝi.

Compare:

• Mi lasis la librojn sur ĝi. = I left the books on it.
• Mi metis la librojn sur ĝin. = I put the books onto it.

A common Esperanto rule is:

• no -n after a preposition for simple position
• -n can appear if there is movement toward a place

Ĝi refers to tablo.

In Esperanto:

• li = he
• ŝi = she
• ĝi = it

A table is a thing, not a person, so ĝi is the normal pronoun.

So:

• sur ĝi = on it
  and it = the table

Because they are all direct objects of lasis.

The verb lasi here is acting on those things:

• I left books
• I left notes/tickets
• I left the passport

So Esperanto marks them with the accusative:

• libroj → librojn
• biletoj → biletojn
• pasporto → pasporton

Even in a list, each direct object keeps the accusative marking.

Because the speaker means:

• more than one book
• more than one bileto
• one passport

So:

• librojn = books
• biletojn = notes / tickets
• la pasporton = the passport

The sentence is simply listing several items, some plural and one singular.

Because la means the, and it is used when something is specific or identifiable.

So the sentence suggests:

• librojn, biletojn = books, notes/tickets in a general sense
• la pasporton = the passport, a specific passport already known in context

For example, your passport is usually a very specific object, so la pasporton sounds natural.

If the speaker meant specific books and specific notes already known to the listener, they could also say:

• la librojn, la biletojn kaj la pasporton

Without more context, the original sentence is perfectly normal.

Senorda is built from:

• sen = without
• ordo = order
• -a = adjective ending

So literally it means without order, that is, disorderly, untidy, or messy.

This is a very common Esperanto word-building pattern:

• sencela = without purpose
• senhoma = without people
• senutila = useless, literally without use

So senorda tablo is an untidy table.

Yes, often it could.

Both senorda and malorda can mean something like disordered / messy / untidy.

But there is a slight difference in feeling:

• senorda = without order
• malorda = opposite of orderly

In many everyday situations, they are very close in meaning. In this sentence, senorda sounds very natural.

Not completely. Esperanto word order is fairly flexible because endings show the grammar clearly.

For example, these are all understandable:

• Mia tablo denove fariĝis senorda...
• Denove mia tablo fariĝis senorda...
• Ĉar mi lasis sur ĝi librojn, biletojn kaj la pasporton, mia tablo denove fariĝis senorda.

However, the original order is smooth and natural. It presents:

1. the main statement first
2. then the reason after ĉar

That is a very common way to structure a sentence in Esperanto.