bodywork novice needing advice

Rust eating my cabrio on rear arch.
I want to repair myself without bodging it,
I can still press on it without going through.
whats the best and latest way to proceed
thanks

HI HAD SAME PROBLEM ON MY CLIPPER BOTH SIDES, BEST BET IS DROP KIT ARCH OFF TO SEE HOW BAD IT IS.  IT WILL MORE THAN LIKLEY IT WILL B WORSE THAN FIRST THOUGHT IF SO IT WILL NEED CUTTING OUT AND NEW SECTIONS WELDING IN NOT A JOB FOR A NOVICE. IF NOT BAD THEN SAND BACK 2 BARE METAL BODYFILL FLAT AND PAINT ONLY PROBLEM MIGHT B MATCH ON PAINT AS IT IS WHITE

8) thanks