Ovaj vikend ću biti ovde.

Both can be used, but they are not exactly the same in feel.

• ovaj vikend is very common for saying this weekend as a time expression.
• ovog vikenda is also possible and often feels a bit more explicitly temporal, like during this weekend.

In this sentence, ovaj vikend is functioning as a time phrase meaning this weekend / over the weekend.

Also note the grammar:

• vikend is a masculine inanimate noun
• for masculine inanimate nouns, nominative and accusative singular look the same
• so ovaj vikend can serve as a time expression without changing the form

ću biti is the future tense.

Serbian future tense is commonly made with:

• a form of hteti (ću, ćeš, će, ćemo, ćete, će)
• plus the infinitive of the main verb

Here:

• ću = I will
• biti = to be

So:

• ću biti = I will be

Because ću is a clitic in Serbian.

Clitics are short unstressed words that usually go in second position in the sentence or clause. They often do not stay directly attached to the infinitive in writing.

So in:

• Ovaj vikend ću biti ovde.

the first unit is Ovaj vikend, and then the clitic ću comes after that.

This is very normal Serbian word order.

Yes. That is also correct and very natural.

Serbian has two very common ways to express this future:

• Ovaj vikend ću biti ovde.
• Biću ovde ovaj vikend.

In the second version, ću + biti is written together as biću.

The difference is mostly about word order and emphasis, not basic meaning:

• Ovaj vikend ću biti ovde emphasizes this weekend
• Biću ovde ovaj vikend starts with the verb phrase and may sound a little more neutral in some contexts

In Serbian, subject pronouns are often omitted when they are already clear from the verb form.

Here, ću already tells you the subject is first person singular:

• ću = I will

So ja is not necessary.

You can add ja if you want emphasis or contrast:

• Ja ću biti ovde, a on neće.
  • I will be here, but he won’t.

Without emphasis, leaving out ja is the normal choice.

Yes. ovde and ovdje are regional/standard variants.

• ovde is the usual Ekavian form, common in Serbia
• ovdje is the usual Ijekavian form, common in Bosnia, Montenegro, and much of Croatia

So depending on the variety:

• Ovaj vikend ću biti ovde.
• Ovaj vikend ću biti ovdje.

Both are correct in their respective standards.

ovde is an adverb of place.

It means here, and unlike nouns or adjectives, it does not change for case, gender, or number.

So:

• ovde stays ovde
• it simply tells you location

That is why the sentence ends with a simple adverb rather than a noun phrase.

ovaj is in the form that matches masculine singular nominative/accusative.

Why?

• vikend is masculine singular
• ovaj has to agree with it
• for masculine inanimate nouns, nominative and accusative are the same

So:

• ovaj vikend = adjective/demonstrative + noun agreeing in gender, number, and case

This is one of the reasons the phrase looks straightforward here.

Yes. Serbian word order is more flexible than English word order.

You could hear variations like:

• Ovaj vikend ću biti ovde.
• Ovde ću biti ovaj vikend.
• Ja ću ovog vikenda biti ovde.

The basic meaning stays similar, but the emphasis changes:

• starting with Ovaj vikend highlights the time
• starting with Ovde highlights the place
• adding ja gives personal emphasis

So the original sentence is just one natural option, not the only possible one.

Because after ću, standard Serbian normally uses the infinitive.

So:

• ću biti = standard future construction

budem is a present/subjunctive-type form connected with da constructions:

• da budem

You may sometimes hear more colloquial speech with ću da budem, but the sentence you were given uses the standard and very common future pattern:

• ću biti

Yes. vikend is a normal, fully accepted word in Serbian, even though historically it comes from English.

Like many borrowed words, it has been integrated into Serbian and behaves like a regular noun:

• vikend
• vikenda
• vikendu, etc.

So learners should treat it as an ordinary Serbian noun, not as a foreign word that stays unchanged outside the language.

Yes, it is completely natural.

A native speaker might also choose small variations depending on style, region, or emphasis, such as:

• Biću ovde ovaj vikend.
• Ovog vikenda ću biti ovde.

But Ovaj vikend ću biti ovde. is normal, clear, and idiomatic Serbian.