Use the search facility for 'spare wheel' and you will see what others have done - not all the same. In my case I took the moulded foam tray out of the boot (easy) and stored it away. Bought a spare wheel bag on eBay. I cut a plywood lid to match the template of the boot tray top lid, painted it matt black then loose-laid it on the wheel with some foam pads at the corners. I already had a GM Antara tough plastic boot tray and this covers everything over. Pack around the wheel with waterproofs, tools, first aid kit and the usual junk we carry around. Job done. Don't forget a jack and wheel brace.
Remember - if you tow a trailer/caravan you should use a matching spare for the car, not a spacesaver or an odd-size spare. The only time I needed the foam repair kit it was hopeless and I learned a lesson from that.
2015 2.2 CDTi SENav 163ps manual 4x4 in Carbon Flash with 19\" alloy spare towing a Bailey Unicorn III Madrid @ 1500kg.