We just tried DS on rice cereal mixed with formula (1:4 ratio - is that correct?) and he did very well with keeping MOST of it in his mouth

(We also got some great pictures of him with a rice cereal mustache). So now I want to start him on cereal and other solids, but have no clue how much to feed him and how often. I know that you're not supposed to fill them up with solids, since they are supposed to get their nutrition from formula. Does anyone have some kind of feeding schedule that they would be willing to share re: starting solids for a 5-month old.
Thanks for your help.