How to Level Concrete for Sliding Patio Doors?
set your door with available shimming it in place then use a 4000 psi rated NON SHRINK grout this will harden and will not allow the door to move .be sure its non shrink use a small trowel  to push to grout under the jam  don't try and get away with only using your hands the trial will help you make sure you have no air bubble so there will be no room for water to fill small voids and freeze causing separation good luck