I was a bit overwhelmed at first too when I started researching the supplementals so I made a spreadsheet to help track the process. Since I submitted my pharmcas application, I've been working on the supplementals one at a time. I'm doing them in the order of schools I have the best chance of getting into, though adjustments are necessary because not all of the supplementals are available at the same time. Figure out a way to organize the process in a way that works for you and it won't seem so overwhelming!