Une architecte vient voir l’appartement afin qu’on sache où mettre la nouvelle étagère.

Because the architect is female, so French uses the feminine article une.

The noun architecte itself often stays the same in spelling for both masculine and feminine:

• un architecte = a male architect
• une architecte = a female architect

So in this sentence, the article tells you the gender.

Vient voir is literally comes to see.

It is made of:

• vient = comes (from venir)
• voir = to see

So Une architecte vient voir l’appartement means the architect is coming to look at or inspect the apartment.

This is a very common French structure:

• venir + infinitive

For example:

• Je viens aider = I’m coming to help
• Il vient chercher son sac = He’s coming to get his bag

Because l’appartement is the direct object of voir.

• voir quelque chose = to see something
• so: voir l’appartement = to see the apartment

If you wanted to say come to the apartment, then you would use à:

• Elle vient à l’appartement = She is coming to the apartment

But here the meaning is comes to see the apartment, not just comes to the apartment.

Afin que means so that or in order that.

It introduces a purpose:

• Elle vient voir l’appartement afin qu’on sache...
• She comes to see the apartment so that we know...

Compared with pour que, afin que is usually a bit more formal or written-sounding.

So:

• afin que = so that, in order that
• pour que = so that

In everyday speech, many people would more naturally say pour qu’on sache.

Because afin que requires the subjunctive.

After expressions of purpose such as afin que and pour que, French uses the subjunctive:

• afin qu’on sache
• not afin qu’on sait

Here:

• sache is the subjunctive form of savoir
• on sache = that one/we may know

This is a classic French pattern:

• Je t’explique cela pour que tu comprennes.
• We’re leaving early afin qu’il puisse venir.

In this sentence, on most naturally means we.

So:

• afin qu’on sache = so that we know

French uses on very often where English would use we in normal speech. It can also mean:

• one
• people
• someone
• they in a vague sense

But here the idea is probably so that we can know where to put the new shelf.

French often uses question word + infinitive where English also can use an infinitive:

• où mettre = where to put
• quoi faire = what to do
• comment répondre = how to answer

So:

• où mettre la nouvelle étagère = where to put the new shelf

A longer version is possible, such as:

• où on doit mettre la nouvelle étagère
• where we should put the new shelf

But the infinitive version is very natural and compact.

Because nouveau / nouvelle usually comes before the noun.

So:

• la nouvelle étagère = the new shelf

Many common adjectives go before the noun in French, especially ones related to things like age, size, beauty, and some very common descriptions. Nouveau is one of those adjectives usually placed before the noun.

While post-noun placement can exist in some contexts, la nouvelle étagère is the normal choice here.

Étagère usually means shelf or sometimes shelving unit, depending on context.

In this sentence, la nouvelle étagère most likely means the new shelf.

French can be a little broader here than English, so the exact translation depends on the situation:

• a single wall shelf
• a shelf in a unit
• sometimes even a small shelving piece of furniture

But shelf is the most likely meaning.

Those apostrophes show elision, which is very common in French.

French drops certain final vowels before a following word that begins with a vowel sound.

So:

• le appartement becomes l’appartement
• que on becomes qu’on

This happens to make pronunciation smoother.

Other common examples:

• je aime → j’aime
• ne est pas → n’est pas
• la école is not possible; it becomes l’école

Yes, a French learner will often notice that a sentence like this could also be expressed differently, for example:

• Une architecte vient voir l’appartement pour savoir où mettre la nouvelle étagère.

That version is also natural and may sound simpler.

The difference is mainly in structure:

• afin qu’on sache = so that we know
• pour savoir = in order to know

The original sentence emphasizes the result for on (we / people involved), while pour savoir is a more direct infinitive structure. Both are possible, but afin que sounds a bit more formal.

Because French often uses the present tense for something that is happening now or is part of a current situation.

• vient = comes / is coming

Depending on context, English might translate it as:

• comes
• is coming

So the French present tense is a bit flexible here. It does not have to mean a timeless general truth; it can describe a current or planned action.

Yes, it sounds somewhat formal, mostly because of afin que.

The more everyday version would often be closer to:

• Une architecte vient voir l’appartement pour qu’on sache où mettre la nouvelle étagère. or
• ...pour savoir où mettre la nouvelle étagère.

So the sentence is perfectly correct, but its style is a little more polished or written than casual spoken French.