Installing a patio after the foundation is laid can be quite easy as long as you start from a corner and work your way out. It is a good idea to install an edger secured with spikes, to prevent the patio stones from shifting along the perimeter As you lay each patio stone down you want to make sure each on is level. There is nothing worse than stepping on a patio and having it wiggle and move. Once you get to the end you may need to use a wet saw to cut the pieces to fit, but if you measured it correctly than it should fit perfectly. Once you have laid your last patio stone you would want to sweep some polymeric or jointing sand in between the cracks, and then mist it with a hose to harden the sand and join you patio together. Paving sealer is the best way to restrict weed growth and prevent you pavers from wiggling and moving around.