If all you need is lights and motion detector lights, vast majority of the posts in that Forum Members Installations won't help you. Not trying to depreciate other people achievements - I've designed and built my solar largely on recommendations of this forum - but you need a relatively small system, perhaps 200-300W array and 100-200 AH battery bank.
Besides, shed roof is not an RV roof, more options for mounting panels and pulling wires. You don't even have to mount it on the roof, a frame of 2x4's placed on the ground out of shade will do. Start with the link in the Pianotuna post maybe. If you ever did any electrical work in your shed, solar won't be a problem.