Probably a failed element. Google is your friend to locate the part and probably some videos of the reaplacement proicess in similar ovens.
Take care.
Check you get the right part
ENSURE THE POWER IS OFF AND THE COOKER IS ISOLATED BEFORE YOU START
Make drawings - DO NOT RELY ON MEMORY.
Have a container handy for screws and make paper notes of from where different screws come.
XXXXX
October 2015