I'm looking to becoming a Trucker.Any info on Driver Solutions CDL training (PAM,USA Truck) What about Swift?

I'm 39 and looking to get into trucking becuz of the pay (i'm thinking long term) Does anyone have any advice about Driver Solutions CDL training (they work with USA TRUCK, Averitt, and PAM)? What about Swift?? Is the DOT drug test urine or hair follicle? ANY ADVICE YOU CAN GIVE a POSSIBLE ROOKIE!!!???