Compounds before isolations? Compound-Isolation-Compound sandwich? Holy options, Batman! Don't worry; check out this video on selecting your exercise order
But do I need to perform them in order every session?
For consistency, it is best practice to perform exercises in the same order each session. It is particularly helpful when it comes to tracking progress for a specific lift/muscle group over the course of the block. However, for most people, exercise order is not going to have a large impact on training results, and sometimes, you need to switch the order due to time or equipment restraints.
If you need to change the order, you can do so by selecting the three dots on the right hand side of the exercise, and then hit move up or move down.