16x2 display not displaying text only white boxes on top row

If your wiring is as described in the message, your constructor would be:

//LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd(7, 8, 13, 12, 11, 10);     // put your pin numbers here

Your wiring is up to you. Quite honestly, life is easier when the wires are in the same order as the Uno pins. e.g. 7, 8, nc, 10, 11, 12, 13 (just like in your original constructor)

If in doubt, copy the example wiring exactly.

David.