Što se tiče programa, predavač će ga objasniti.

Yes. Što se tiče + genitive is a very common fixed expression meaning as for, regarding, when it comes to, or as far as ... is concerned.

So:

• Što se tiče programa = as for the program / regarding the program

You should learn it as a chunk, because speakers use it very often to introduce a topic.

Because što se tiče requires the genitive case.

The base noun is:

• program = nominative singular

After što se tiče, it becomes:

• programa = genitive singular

This is just part of the pattern:

• što se tiče programa
• što se tiče predavača
• što se tiče škole

So if you use što se tiče, expect the following noun to be in the genitive.

Because the verb here is ticati se, which is used with se.

So the core verb is not just ticati, but ticati se in the sense of to concern / to relate to.

That means:

• to se tiče programa = that concerns the program
• što se tiče programa = as for the program

In other words, se is not optional here. It belongs to the expression.

Ga is the unstressed pronoun meaning him / it in the accusative singular masculine.

Here it refers back to program:

• program is masculine
• therefore it = ga

So:

• predavač će ga objasniti = the lecturer will explain it

Serbian often avoids repeating the noun if it has just been mentioned, just like English does.

You could say that too.

Compare:

• Što se tiče programa, predavač će ga objasniti.
• Što se tiče programa, predavač će objasniti program.

The second version repeats program, which is grammatically correct but usually sounds less natural because the noun was already mentioned. Using ga is smoother and more natural.

So ga is there mainly to avoid repetition.

Yes, both are possible, but the word order follows Serbian clitic rules.

Future tense here is built with:

• će
  • infinitive

So the basic idea is:

• će objasniti = will explain

But će is a clitic, and ga is also a clitic. Clitics usually go near the beginning of the clause, in second position.

That is why you get:

• predavač će ga objasniti

If the verb comes first, you often see the future attached to it:

• objasniće ga

So these are both natural:

• Predavač će ga objasniti.
• Objasniće ga predavač.

But predavač će objasniti ga sounds wrong, because ga normally cannot sit there at the end like that.

Because objasniti is the perfective verb, and it fits the idea of a single completed future action: the lecturer will explain it.

In Serbian, aspect matters a lot.

• objasniti = perfective, to explain successfully / to give the explanation
• objašnjavati = imperfective, to be explaining / to explain repeatedly / to explain in an ongoing way

In this sentence, the speaker is talking about one future act of explanation, so objasniti is the natural choice.

Sometimes you may hear šta se tiče in speech, but što se tiče is the standard and most widely accepted form of this expression.

So for learners, the safest choice is:

• što se tiče

It is best to memorize the whole phrase exactly that way.

Because što se tiče programa is an introductory topic phrase.

It sets the topic first:

• As for the program, ...

Then the main clause follows:

• predavač će ga objasniti

In English, you would also often use a comma after as for the program or regarding the program, so the punctuation works similarly.

The sentence can be rearranged somewhat, but not completely freely, because the clitics će and ga have placement rules.

Natural versions include:

• Što se tiče programa, predavač će ga objasniti.
• Predavač će ga objasniti, što se tiče programa.
  This is possible, but less neutral.
• Predavač će objasniti program.
  Also natural, with the noun repeated instead of a pronoun.
• Objasniće ga predavač.
  Possible, but more marked for emphasis.

The original sentence is neutral and very natural if you want to introduce program as the topic first.

Because Serbian has no articles like a and the.

So predavač can mean:

• a lecturer
• the lecturer

The exact meaning depends on context.

In this sentence, context probably makes it clear which lecturer is meant, so Serbian does not need a separate word like the.