19 years old, just graduated HS. Will be running for a small D-3 college in Iowa this fall. Running XC (8k) this fall so I would love to dip down to the 16:30s in the 5k by July or August. PRs in HS were 50.4, 2:00, 4:47, and 17:36 5k. I recently got an high altitude training mask for my birthday and I have no idea what to do with it running wise. I am capable of running 10 milers at 6:50 pace for normal training so would I be wearing the mask for my long runs and my speed work? I know you have to build up full strength with the mask so what would I do first? Start easy like 5 milers at 7:30-8:00 pace and then change the valves on the mask as my lungs get stronger? I honestly don't know anything about it and would appreciate some feedback. Thanks in advance.