BYU's first game is September 3rd. If they start this coming Monday which is July 13th that means it is 8 weeks until the first game.

Week #1 - July 12th-18th Conditioning
Week #2 - July 19th-25th Conditioning
Week #3 - July 26th - August 1st Fall Camp
Week #4 - August 2nd - 8th Fall Camp
Week #5 - August 9th - 15th Fall Camp
Week #6 - August 16th - 22nd Fall Camp
Week #7 - August 23rd - 29th Fall Camp
Week #8 August 30th - September 3rd Game prep

The BYU vs Utah game is on a Thursday so I think by the rules they could have started mandatories today but they didn't and instead are starting them Monday.