How does live sand affect a new tank?

I know there are a few different ways to start a tank but I like the idea of using a little bit of LR with some base Rock and let it do its thing. It seems the other popular way is just to use a deli shrimp with base Rock and add live rock later if wanted. So how does live sand affect this? Is LR or a shrimp necessary when using live sand? Isn't the sand (or other substrate) basically the first thing to add to a tank? I don't plan on using it DSB, just using sand as my substrate.

Thanks!