try contacting Belling for a manual:
http://www.belling.co.uk/customer-care/manuals/?q=110wgr
If its a 5 button timer there's plenty pf advice around, typically:
http://www.caple.co.uk/downloads/manuals/ovens/electronic-programmer.pdf
3 button timers are more of a varied bunch
XXX
April 2016