The bets are determined by checking a wide variety of projections against my own knowledge of how players will be utilized given game context. The player prop lines were taken from this site.
When analyzing projections from fantasy sites, you'll often find that the projections are higher than betting lines, which will make you bet shit tons of overs. This is a common mistake. The projections are mean based, while the betting lines are median. Mean projections tend to skew higher because the range of outcomes are not evenly distributed. (i.e., a running back on a good day could go for over 100 yards, but he would never go under 0... hopefully). If you find a mean projection lower than the Vegas line, the under is likely a good bet. To bet an over, the mean projection should be significantly higher. All bets below will follow that logic.
Sunday 1PM Slate
Josh Allen u214.5 passing yards -113 (FanDuel)
Daniel Jones o205.5 passing yards -110 (Bet365)
Kenneth Walker u70.5 rushing yards -115 (BetMGM)
Sam Laporta u43.5 receiving yards -110 (Bet365)
Darius Slayton o27.5 receiving yards -113 (FanDuel)
Sunday 4PM Slate
Alexander Mattison u38.5 rushing yards -110 (Bet365)
Jordan Mason o57.5 rushing yards -115 (BetMGM)
Colby Parkinson u41.5 receiving yards -120 (Bet365)
Monday Night Football
Kyler Murray u220.5 passing yards -110 (Bet365)
Cade Otton u39.5 receiving yards -110 (Bet365)