How to replace Tank Water Heater with a Tankless Electric Water Heater

The parts I used for this install are: 1) One (1) - Rheem Performance 27 (RETEX-27) GPM Tankless Electric Water Heater @ $ - $ 2) One (1) - Southwire 125 ft. 8/2 Black Stranded Romex SIMpull CU NM-B W/G Wire @ $ - $ 3) One (1) - Carlon 1 in. x 25 ft. Electrical Nonmetallic Tubing Conduit Coil, Blue @ $ - $ 4) One (1) - Carlon 1 in. ENT Male Adapter (Standard Fitting) @ $ - $ 5) One (1) - Halex 1-1/2 in. x 1 in. Rigid Conduit Re