Adventure Game Studio

I got the pillow and gave it to Karl, but how do I get him to make me a costume from it? I have the other two books already.

There's a frog costume in the shop that's will be used as the pattern for the disguise. If you haven't done so yet, use Karl on the frog costume and then use Karl on yourself. The alien should comment something about looking ridiculous and your sprite will change slightly (it's pretty subtle) indicating you are in disguise.

I got book 1 & 3 but I don't know how to get food from the vendor...? :P 

have the gloves? You picked them up, right? In the space ship, to the lower right

At the playground, South of the girl and the tree-house, use the gloves on the waste bin