Strongly suggest doing away with sandbed if you don't mind. Everyone likes clean white sandbed that mimics the oceanbed and looks more natural, but the reality is you will probably be fighting all sorts of algae growth like diatoms, red slime to name a few.
Anyway to answer your qn: the easiest method would be add 1)sand, 2)scape rock, 3)NSW delivery. Just push the rocks deeper into the sandbed to prevent them from sand shifters.
If you are using salt mix, unless you have a huge container to mix your salt (or its a nano tank), most likely is add 1) water into tank, 2) mix salt, 3)sand, 4) LR.
If you are not going for SPS, strongly suggest going through NSW, less hassle and hard work. Check with LCK if they do delivery.