Danas imam sastanak koji počinje u osam sati.

Yes. Danas means today, and Serbian word order is fairly flexible.

Putting Danas first is very natural because it sets the time frame right away. It is similar to saying Today, I have a meeting... in English.

You could also hear:

• Imam danas sastanak...
• Imam sastanak danas...

But Danas imam sastanak... is a very normal, neutral way to say it.

Serbian does not have articles like a or the.

So imam sastanak can mean:

• I have a meeting
• I have the meeting

The exact meaning depends on context. In this sentence, English naturally uses a meeting, but Serbian does not need a separate word for that.

It is in the accusative singular because it is the direct object of imam.

The verb imati means to have, and its object normally goes in the accusative:

• Imam knjigu = I have a book
• Imam sastanak = I have a meeting

Because sastanak is a masculine inanimate noun, its accusative singular looks the same as its nominative singular:

• nominative: sastanak
• accusative: sastanak

So the form does not change here, even though the case does.

Koji means which, that, or sometimes who, depending on what it refers to.

Here it refers back to sastanak, so the phrase koji počinje u osam sati means which starts at eight o’clock or that starts at eight o’clock.

In Serbian, koji must match the noun it refers to in gender and number, and its case depends on its role inside the relative clause.

Here:

• the noun is sastanak
• sastanak is masculine singular
• inside the relative clause, koji is the subject of počinje

So the correct form is koji: masculine singular nominative.

Because koji agrees with sastanak, which is masculine singular.

The basic forms are:

• koji = masculine singular
• koja = feminine singular
• koje = neuter singular or some plural uses

Since sastanak is masculine singular, you need koji.

For comparison:

• knjiga koja... = the book that... because knjiga is feminine
• pismo koje... = the letter that... because pismo is neuter

In standard Serbian, koji is the normal choice here.

When you have a clear noun like sastanak and then a relative clause describing it, koji is the safest and most standard option:

• sastanak koji počinje...

Što can appear in some varieties of speech and in some other structures, but for a learner, koji is the form to use in sentences like this.

A useful rule of thumb:

• after a specific noun: usually koji
• after words like sve, ono, nešto: što is very common

Because its subject is koji, which refers to sastanak.

So the meaning is:

• the meeting starts not
• I start

That is why the verb matches sastanak, not ja.

The pattern is:

• sastanak počinje
• koji počinje

Both are third person singular.

Because počinje is the imperfective present form, and that is the natural choice for a scheduled event like this.

Serbian often uses the imperfective present for timetabled or planned events:

• Film počinje u devet.
• Voz kreće u šest.
• Sastanak počinje u osam.

Počne is from the perfective verb početi, and it is used in different situations, for example:

• Kad sastanak počne, pozovi me. = When the meeting starts, call me.

So in this sentence, počinje is the normal form.

Because Serbian, like English, often uses the present tense for scheduled future events.

English does this too:

• My meeting starts at eight tomorrow.

Serbian works similarly:

• Sastanak počinje u osam.

This is especially common with:

• schedules
• appointments
• transport
• events with a fixed time

So even though the meeting is later, počinje is completely natural.

It means at eight o’clock.

The preposition u is used here for a specific clock time:

• u jedan
• u dva
• u pet
• u osam sati

So:

• u osam sati = at eight o’clock

This is a standard way to express exact times.

Because after numbers five and higher, Serbian normally uses the genitive plural form of the noun.

With sat:

• jedan sat
• dva sata
• tri sata
• četiri sata
• pet sati
• osam sati
• deset sati

So osam sati is correct because osam is higher than four.

This number pattern is very important in Serbian.

Yes. In everyday speech, u osam is very common and completely natural.

So both of these work:

• Danas imam sastanak koji počinje u osam sati.
• Danas imam sastanak koji počinje u osam.

The version with sati sounds a little fuller or slightly more explicit, but both are correct.

Yes, absolutely.

Danas imam sastanak u osam sati is probably the more straightforward everyday way to say I have a meeting at eight today.

The version with koji počinje is also correct, but it is a bit more explicit:

• imam sastanak u osam sati = I have a meeting at eight
• imam sastanak koji počinje u osam sati = I have a meeting that starts at eight

In many real situations, those mean almost the same thing. The longer version just spells out the idea of starting more clearly.