Question

[shrewd sage]

When there is an indefinite article do the au aux rule apply

[rough heart]

Au is à + le, aux is à + les, there are no other combos that create them, partitives don't contract after a preposition
à + du = à du
à + des = à des
Note that after the preposition "de", the partitive disappears :
de + du = de
de + des = de
Which allows the preposition to clearly contract with definite articles :
de + le = du
de + les = des

[shrewd sage]

Oh

It’s getting really hard 💀

[shrewd sage]

I have a lot to learn

Thank you

[rough heart]

This is one of the trickiest concepts for learners imo, simply because things look so similar it can be hard to conceptualize them properly

Genuinely the 2 hardest things imo are "de" usages and imparfait vs passé composé, for learners (coming from English at least)

[shrewd sage]

Coming from English too