Depends on how you want to do it.
If you're using it for just PCT, I would run it at 15-25 mgs ED for 4 weeks. If you're wanting to use it to bridge between cycles then run it at 25 mgs for the full 8 weeks.
Try out Sarms1 if you haven't yet - getting rave reviews so far as best quality and purity on the net. And don't forget to shake your sarms well before use!
Good luck