Waterproofing basement shower?

I just finished framing out a shower for our basement and need help with understanding the principle of waterproofing. Being that it is constructed on a cement floor already, is it required to put a waterproof menbrane on the shower floor?? Can I use 1/2 inch cement board and mortar all the joints? Can i use cement board to construct the shower curb instead of building it with mortar? I want to tile the entire shower so will that help with the waterproofing? Any suggustions will be great. Thaks

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