I ni ce, @Caroline! Just like in this topic, you need build a relative sentence using min. The word “what” in the English sentence is doing the work of making the sentence a relative in English as well.
So how about something like this:
Aw ye min kɛ, n bɛna o filɛ kɔfɛ.
Lit. “That which you all did, I will look at that later”