Thanks for the question! So generally speaking, you’ll be given something like
P: A P: ?? C: C
And so you need to figure out what to add to get to the conclusion. So you want to start off with the premises in the sufficient, and get to the conclusion in the necessary, for example. So here, you want
A —> C
which is the second premise that connects the first premise and the conclusion. That’s the general structure of how to approach these problems.
Hope this helps! Feel free to ask any other questions that you might have.