How to skip preprocessing ?

Hello dear conn-ers:

Thank you so much for developing this great toolbox !

I just have 2 quick questions,

1) To skip preprocessing, what structural and functional files should i choose in the set up in the gui?
2) If I want to add some more specific ROIs in the setup, does this mean that every time I change the ROI set up, I need to re-run the pre-processing again?

It would be of great help if you could help me out, any information is highly appreciated !
Thank you so much!

Best,
Zoe