This is a personal choice if you prefer to wash your fabrics or not before you use them. Personally I like to use my fabric unwashed as it has a crispness about it making it easier to sew with but you may like to use your fabric with a softer feel. With good quality cotton the colours should not run but you sometimes can get some leakage with the reds but if you put a colour catcher in with the quilt when washed this should prevent any darker colours leaking into the lighter fabrics if you do not wish to pre wash. If your unsure then my advise would be to colour fast test a small piece of the fabric before use.
If washing your fabric by machine it should be unfolded before placing into the machine. Wash light and dark fabrics seperately. Soak dark fabrics for about a hour in cold water before machine washing, and use a non bio product.
Set the washing machine to a low spin. The fabrics can be tumble dried but remove when slightly damp and press with an iron.