On the plates that are arranged in different manners, you have to place the letters in the right order to make up words that fill them up, simple as that. To make the words you use the mouse, drawing lines between them in the correct sequence, with the words being found on the dishes at the bottom of the screen.
For all the words that you create right, you are going to get coins in return, of which you should try to gather as many as possible, using them to help you out and buy hints, in case you think they would be necessary. As you progress through the levels, there are going to be more letters to use, and bigger words to make, so it gets more exciting and fun.