We can’t tell you how much to use because your body chemistry and personality are an important factor, as are factors concerning you targets. This is where you have to do a little work to find what works for you.
Have a read of this thread that covers all the basics of phero use, especially the “finding you sweet spot” post, which shows how to get the best dose most efficently:
Fo application points - This thread is great:
A bit more info about yourself and your opportunities to use pheros would help us offer better advice and it will also earn you the GC. Have a read of this for an idea of whats needed: