We are having our front walk and porch covered with Arkansas fieldstone pavers using mortar. The walk and porch are currently old concrete in reasonably good condition. I don't really have too much confidence in my installers and want to be sure it is done correctly.

I have seen many overlaid walks with loose stones and would like to avoid this happening as much as possible.

Should a bonding agent be used over the old concrete before applying the new mortar base? Should the pavers be cleaned or prepped in any way? What about curing, should the walk be covered to keep it moist for as long as possible. It is still fairly warm weather here and may get hotter before it is done(90's).

Any pointers will be appreciated.

Thanks