Pouring a small slab for a shed, patio, or pad is achievable for a prepared DIYer, but concrete is unforgiving — once it's in, you have limited time to get it right. Preparation is most of the job.
Base and forms
Excavate and lay a compacted gravel base for drainage and support, then build level wooden forms to hold the concrete to the right shape and thickness — typically 4 inches for a patio. A solid, level base prevents cracking and settling.
Reinforce
Add wire mesh or rebar on supports so it sits within the slab, not on the ground, to control cracking. Plan control joints to direct where the inevitable shrinkage cracks form.
Pour and finish
Pour and spread the concrete, screed it level with the forms, then float the surface smooth. Work in your control joints and edge it. For a non-slip finish, broom it. Keep it damp as it cures over several days for full strength — concrete gains strength slowly.