To a foundation: start with an ace, then build up in the same suit — A, 2, 3 and so on to king.; Within the tableau: build down in alternating colours — a red six onto a black seven.; A face-up run may be moved as a unit if the sequence stays valid.
Why people argue about this
People often think they can only move face-up runs as units if all cards are in sequence from top to bottom of the run, but actually, you can move them even if there's a mix of different sequences within the same alternating color pile, as long as it maintains the valid build rule — moving down in alternating colors.
