Ovo je važan sastanak.

Because ovo here means this in the sense of this thing / this here. In Serbian, when you point something out and identify it with to be, you often use ovo even if the noun that follows is masculine, feminine, or plural.

So:

• Ovo je važan sastanak. = This is an important meeting.
• Ovo je moj brat. = This is my brother.

By contrast, ovaj usually directly modifies a masculine noun:

• ovaj sastanak = this meeting

So:

• Ovo je važan sastanak. = a full sentence
• ovaj važan sastanak = a noun phrase, not a complete sentence by itself

Je is the 3rd person singular present tense of biti = to be.

So:

• ja sam = I am
• ti si = you are
• on/ona/ono je = he/she/it is

In Ovo je važan sastanak, je simply means is.

Because Serbian adjectives must agree with the noun in gender, number, and case.

The noun sastanak is:

• masculine
• singular
• nominative

So the adjective must also be:

• masculine
• singular
• nominative

That gives važan.

Compare:

• važan sastanak = important meeting (masculine)
• važna knjiga = important book (feminine)
• važno pitanje = important question (neuter)

In Serbian, many nouns ending in a consonant in the dictionary form are masculine. Sastanak ends in -k, so it is masculine.

That is why you get:

• važan sastanak
• not važna sastanak
• not važno sastanak

A useful habit is to learn new Serbian nouns together with their gender.

Both are in the nominative singular.

In a basic identifying sentence with to be, Serbian usually uses the nominative:

• Ovo je važan sastanak.
• To je veliki problem.
• Ona je dobra profesorka.

Since važan describes sastanak, it matches it in case as well as gender and number.

Serbian has no articles, so there is no direct equivalent of English a/an or the.

That means važan sastanak can mean:

• an important meeting
• the important meeting

The exact meaning depends on context.

For example:

• Ovo je važan sastanak. could mean This is an important meeting
• In another context, it could also mean This is the important meeting

The most neutral word order is:

• Ovo je važan sastanak.

But Serbian word order is more flexible than English, and changing it can shift the emphasis.

For example:

• Ovo je važan sastanak. = neutral
• Važan je ovo sastanak. = marked, emphasizing important
• Sastanak je važan. = The meeting is important

So yes, other orders are possible, but the original sentence is the most natural basic form.

In Serbian, adjectives usually come before the noun they describe, just like in English.

So:

• važan sastanak = important meeting
• velika kuća = big house
• dobar čovek = good man

That is the normal order. Post-noun adjectives are much less common and usually sound literary, specialized, or stylistically marked.

Yes, ovo can be used for people when you are introducing or identifying them.

For example:

• Ovo je Ana. = This is Ana.
• Ovo je moj profesor. = This is my professor.

So ovo does not have to match the gender of the noun that follows. It often works more like this here / this person / this thing in an identifying sentence.

Je is a clitic, which means it is a short unstressed word that normally goes in the second position of the sentence or clause.

That is why you get:

• Ovo je važan sastanak.

Not normally:

• Ovo važan je sastanak.

This second-position behavior is very common with forms like sam, si, je, smo, ste, su and also with some pronouns.

So the placement of je is not random; it follows a regular Serbian pattern.

Yes, you can say:

• Ovaj sastanak je važan.

That means This meeting is important.

It is slightly different in structure from:

• Ovo je važan sastanak. = This is an important meeting.

The difference is:

• Ovo je važan sastanak. identifies something: This is an important meeting
• Ovaj sastanak je važan. starts with the meeting itself: This meeting is important

Both are correct, but they are not exactly the same sentence pattern.

A few useful pronunciation points:

• ž sounds like the s in measure
• j sounds like English y in yes
• c would sound like ts, but there is no c in this sentence
• sastanak is pronounced roughly SA-sta-nak
• važan is roughly VA-zhan

Very approximate English-style guides:

• ovo ≈ OH-vo
• je ≈ yeh
• važan ≈ VAH-zhan
• sastanak ≈ SAH-stah-nahk

These are only approximations, but they are a helpful start.