I am making the simple cat (the one with the head that looks like a box) and need a little help. I know what lines are valley folds and mountain folds but there are solid lines that I don't know what kind of fold it is. Here is the crease pattern:
As long as you can distinguish between the 2 types of folds you will get to the finished model. The only thing that knowing which are valley and which are mountain folds will do for you is change which side of the paper faces out. You could always fold one, guess which is valley/mountain and then if it turns out that the wrong side is facing out, fold another.