how to input acompcor regressors into proc.py for resting state analysis

hello afni experts,

I would like to run a resting state analysis and include a file that contains compcor regressors (5 principal components for wm, 5 PC for csf) for nuisance regression which I created using a different software. After reading through afni_proc.py help and other documentation, it is still not clear to me what option I should use to input this file? Is it
-regress_use_stim_files? also is there any specific format the file needs to be in? Is .txt ok?

Thank you very much in advance
Carolin