hi Oliviab. you probably clicked on the link from the homepage or maybe from the post I put on talk. there are normally three or so ways to enter like send in a tip, or a recipie, or a review each competition may have different entry requirements.
jambo1707 -- competitions run weekly, check out the home page there is a link to the weeks competition. also you can look at the competitions thread where I post info each week.
enter away there are some really nice ones planned.