Will was hungry. While he wasn't the best cook, he liked to think he could make good enough food on his own. Maybe Camp Half-Blood should have prepared them more for having to cook for themselves, but considering most demigods didn't live into their adult years, maybe they didn't think they had to bother.
"Oh, uh... Yeah. I just came to make something." Something being the primary word. He had no idea what he wanted to make. He just knew his demigod appetite was yummy.