The word list on the right of the grid shows the words you have to search for. You can scroll through long lists.
Search the grid for one of the words. When you think you have found it, use the mouse to highlight the word on the grid. If you are correct, the word will be circled in red on the grid and it will turn grey in the list.
If you are using a tablet or smartphone, you can use gestures instead of a mouse.
If you are struggling to find a word, click on it in the list, then click on the Show word button. You can clear it all by clicking Undo all, or give up by clicking Show solution.