how do i relight my aga?

weve just moved home and for the first time now own an aga which is an oil burning, twin heating top plate model not exactley sure how old it is would say around 15/20 years and white in colour. its in lovely condition and we have the paperwork to say it has had regular services the old owners of the house advised us to turn off the aga when the weather got warmer (last june) so we did. Now the weather has changed again i have forgotten how to relight it safely and correctly (derh). Would this be a good time to try and clean out the burner, if so can anyone advise