prt = xff('nameofprtfile'); %load up your prt file
%next, transform this into an sdm object with a few options:
%nvol refers to number of volumes
%prtr refers to the TR in ms
%rcond refers to which condition is a rest condition, you must specify this as empty '[]' if you don't want it to take anything out as a rest condition
%otherwise it takes out I think last column as a rest condition (or perhaps the column labeled as 'rest', not sure).
sdmfile = prt.CreateSDM(struct('nvol',260,'prtr',2000,'rcond',[])); 
sdmfile.ShowDesign %outputs a figure of your design!