I'm advising on the most common cause of the fault.
There are other causes, quite rare so if you find the element is ok, let me know and I'll advise further.
Isolate the power to the appliance. Disconnect it from the electrical supply
As the fan is running and the temperature light is coming on, then the most likely cause of the problem is a failure of the circular element in the oven.
The method of changing will depend on the element fitted at the time of manufacture.
There are 2 types, one is held from the front by screws, the other is held from the rear by nuts.
The manual suggests your one is held from the rear by 7mm nuts.
For this, you need to pull the appliance out and take the rear panel off.
Near the fan motor you'll see the element coming through.
Label the wires and disconnect them from the element.
Take the nuts off.
Take the rear panel inside the oven out.
This will reveal the element and the fan.
Take the screws holding the element in place out.
Bring the element and the wiring into the oven cavity.
If the element is not obviously blown, you need to test it with a multimeter to see if it's open circuit.
Fit the element in place and replace the cover.
Reconnect the wiring and secure the element with the nuts.
Replace the rear panel.
Turn the power back on and set the clock (if necessary).
Try the oven again.
If the element tests ok, let me know.
Hope this helps
Let me know how it goes or if you need more help