If you find yourself doing a module on things you think you already know, there may have been a problem with your diagnostic. To correct this mistake, you can take a mini-diagnostic to complete the module straight away (and move on to other work).
To do this you first click on the 'Stop' button on the module page:
You should then click on the 'I can already do this - I'd like to show what I already know.' button. This will show you some information about what's happening, and you can then click the 'Okay' button to take you to the mini-diagnostic.
If you get the question on the mini-diagnostic correct, that module will be mastered and you can go on with new work. If you get it wrong, you'll have to go back to that module and complete it normally.
When you have to click this button a lot it might mean that you're being given lots of work too easy for you, so your teacher might get you to re-do a diagnostic test to check that you're getting the right level of work. Your teacher will get an email about this and will talk you through the options.
If you think that the level of work is fine but you're just finding a module easy, it might be better to just add the module to your next test using the 'Finish' button.
If you're not sure whether your work is generally too easy or not, have a chat with your teacher about it.