If your not comfortable drilling your tank then you don't need to. Overflows are not that expensive and don't really take anything away from the tank, Ive always used a overflow that hangs on the back or side of the tank. To start find a good place to put your tank on stable ground and away from any sunlight then make sure you pre-mix your salt in RO
water or at least distilled water and get it in the tank and add some sand and your pretty much started!! You can do this before you set up a sump no big deal. Do you have any type of filter at the moment? And read read read as smitty suggested to start a cycle and all that fun stuff!