I'm with Barry that first you need to get access to the car. Then you need to decide what your goals are for the car, meaning what you want it to do: go racing, go cruising, shows, whatever. Then mock up any changes to the car so all the fabrication/alteration work is done. Then tend to the bodywork & paint, with the engine bagged or out of the car (overspray). Interior after paint. Detailing & trim comes last.
Is that a Healey hardtop leaning against the car?