U ovom članku radi se o tome kako mladi ljudi štede novac za stan.

Yes, raditi often means to work or to do, but in the expression raditi se o + locative, it means to be about or to concern.

So:

• Radi se o tome... = It is about...
• U ovom članku radi se o tome... = This article is about...

This is an idiomatic expression, so it is best not to translate it word for word.

In radi se o, se is part of the fixed expression. It helps make the construction impersonal, similar to English it is about.

So you should learn raditi se o as a whole pattern:

• Radi se o sportu. = It is about sport.
• Radi se o problemu. = It is about a problem.

Without se, the meaning would be different.

This is a very common Croatian structure:

• radi se o tome kako...
• literally something like it is about that/how...
• naturally in English: it is about how...

The pronoun to becomes tome because the preposition o requires the locative case.

So:

• to = that / it
• o tome = about that / about it

Croatian often uses this extra pronoun before a subordinate clause, where English would usually just say about how...

Because u here means in, and it refers to a location, not movement. With that meaning, u takes the locative case.

Compare:

• ovaj članak = this article (nominative)
• u ovom članku = in this article (locative)

Both words change because ovaj and članak have to agree in case:

• ovaj → ovom
• članak → članku

Because ovaj is the basic form, but after u meaning in, you need the locative case.

Masculine singular ovaj changes like this:

• ovaj = nominative
• ovog / ovom / ovim etc. = other cases

Here the correct form is ovom because it agrees with članku in the locative:

• u ovom članku

Here kako means how.

It introduces the idea that follows:

• kako mladi ljudi štede novac za stan
• how young people save money for an apartment

So the sentence is talking about the way / process by which young people save money.

In other contexts, kako can also mean as or the way that, but here how is the best translation.

Because mladi ljudi is the subject of the clause, so it is in the nominative plural.

• mladi = young (masculine plural nominative)
• ljudi = people

A useful thing to remember: ljudi is an irregular plural form. It is the plural of čovjek (person / man), not of a singular ljud.

So:

• mlad čovjek = a young person / young man
• mladi ljudi = young people

Because the subject mladi ljudi is third person plural, so the verb must also be third person plural.

The verb is štedjeti = to save.

Present tense:

• ja štedim = I save
• ti štediš = you save
• on/ona štedi = he/she saves
• mi štedimo = we save
• vi štedite = you save
• oni/one štede = they save

So:

• mladi ljudi štede = young people save

Also, štedjeti is an imperfective verb, which fits well here because the sentence describes a general or ongoing activity.

Because novac works like money in English: it is normally treated as a mass noun.

So Croatian usually says:

• štedjeti novac = to save money

You may sometimes hear novci / novce in everyday speech, but novac is the standard neutral form here.

Here za means for, in the sense of for the purpose of getting/buying something.

In this meaning, za takes the accusative case.

• stan is masculine inanimate
• for masculine inanimate nouns, accusative singular is the same as nominative singular

So:

• stan = apartment / flat
• za stan = for an apartment / flat

The phrase means they are saving money with the goal of getting or buying a place to live.

Because Croatian does not have articles like English a/an and the.

So Croatian simply says:

• stan = apartment / the apartment / an apartment

The exact meaning depends on context.

In this sentence, English would usually say for an apartment or for a flat, because that sounds most natural.

Words like ovaj (this) can make something more definite, but Croatian does not use articles the way English does.

Croatian word order is more flexible than English word order. This sentence is natural as written, and it starts with U ovom članku to set the context first: In this article...

The most important thing is still the grammar and case endings, which show how the words relate to each other.

So even if the order changes somewhat, the meaning often stays the same. But the given order is a very normal written style for introducing a topic.