What you need to do is remove the back panel inside the oven.
From there you will see the fan and element.
You need to remove the fan. This sometimes isnt easy.
Remove the nut its an opposite thread so turn the nut clockwise to remove.
Now the hard part the fan will need to be pulled off. If its not comming off easy try pushing it backwards and forwards to work it loose then it will come off.
Then when the fan is off you will see the screws holding the element on.
2 either side and 1 in th middle. Remove these and pull element out and swap wireing on to new element and then refit in reverse order.
If you need anymore info just get back to me.
The back panel inside the oven is easy to get off.
You will just see the screws holding it on just remove them and the back panel will come off then.