Joe, stop talking to whoever said to use liquid nails to secure the Durock, they don't have a clue!
All the backerboard companies have instructions for properly installing their products. Your best bet is to read them and follow them to the letter. Most of the manufacturers agree on the installation methods, so there are general rules you can follow.
To summarize:
1) On Walls: Staple the vapor barrier to the studs. Use 15# roofing felt or 6-mill poly sheet. Using backerboard screws or galvanized roofing nails, attach the backerboard to the studs, screwing (or nailing) every 3 to 6 inches along the edges. Make sure all edges are supported by studs or blocking.
2) On Floors: Layout the backerboard so that no more than 3 sheets meet and no seam lines up with a plywood seam. Apply thinset to the plywood with a notched trowel and attach the backerboard to the plywood with backerboard screws or galvanized roofing nails. Screw (or nail) every 3 to 6 inches along the edges and 8 to 12 inches everywhere else. DO NOT screw or nail into the joists, even if you have to alter the screw pattern.
3) On Both Walls and Floors: Use alkli resistant fiberglass cloth tape (CBU tape) and thinset to tape and mud the backerboard seams. You can wait and do this as you tile to avoid "speed bumps" that will be difficult to tile over.
This is a common subject, so if you do a site search, you'll find a lot more to read. However, the best source of information is the manufacturer's instruction sheet or website.
Good Luck!
Bob
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