the concrete pad, is that something someone can do without experience, or is it a tricky thing to get right, like plastering?
It ain't rocket science, the important bit is the prep must be done properly so on the day you pick to lay the concrete all you have to do is mix it, shovel it in and screed it off so it's smooth. Getting the shuttering put together in advance and making sure it's level and you have all the stuff you need to hand is 90% of the job. Making sure you have actually got enough aggregates and cement, plus any additives you are going to use, and a tarpaulin on standby to lay over the top in case it pisses down after laying before it's gone off.
I did my 10' x 6' 8" x 6" tool shed base in one day, mixing it up by hand with a shovel on a sheet of old plywood - no new-fangled cement mixer! It was hard work and once you start you can't stop, you just have to crack on until it's all done as you don't want the first stuff down going off before the last bit is laid. I used some sort of retarder/plasticiser additive to slow it down so it was always being laid wet-on-wet. I had also got some steel weldmesh out of a skip prior to doing the job and used that as reinforcement for the slab. Also put a bit of well smashed up brick/concrete hardcore into the hole to reduce the volume of aggregates needed. My sledge hammer was busy the day before!