Hi !
The easiest way is to buy for your A1200, original WB 3.1 + rom kick 3.1 at
VesaliaThen prepare (hdd install disk) HDDToolBox [good luck !], then Format (with the menu on top), then install WB, and then add "PC0: " for storage/DOS to DEVS/DOS this will allow you to transfert data on PC Formated 720 kb disk.
Then found a IDE driver such as IDEFIX or ASIMCDFs on AMInet.
Easy !!