The next step in installing your brick paver patio once you have completed compacting the base material is to lay out 1" diameter black plumbing/gas pipe every 5-7' as screed rails. You will set the height of the screed rails exactly the height of your brick underneath the string lines that you have strung across your patio. You will first set the ends of the screed rail and then you will lightly pack sand underneath the middle so that the center of the screed rail cannot droop or sink, causing a possible dip in your brick patio.
You will then take and spread sand between the screed rails and then take a board and sreed the sand across the screed rails. Once you have screeded the sand across the rails, gently and carefully remove the screed rails and set them off to the side. You are ready to start installing your brick.
When you come to where the screed rails were located you will carefully trowel some sand in the hollowed out places where the rails were located and trowel out that sand so that it is smooth. You may then continue laying you brick.