The expectation is that when someone wants to start a SW tank, that they will do at least some research on setting one up
prior to actually doing it. If you wanted to take up skydiving, would you ask questions AFTER you jumped out of the plane? Dangerous you say eh?
You need to learn about the 'nitrogen cycle' - commonly called 'cycling a tank'..I'm sure you will get something like a million hits of you Google it.
(oops, I checked... 2 1/2 million...)
Some research on your own would be a good idea
We are forever suggesting that new reefers read as MUCH as they can!
...why you shouldn't be using fish to cycle a tank...because the ammonia generated by the cycle burns their gills, for days & days...causing damage and often killing the fish.
There are so many ways that are humane to cycle a tank without harming fish in the process.
Water from someone else's tank contains so little bacteria, there isn't any point in using it. The bacteria that is important is on the surfaces or everything in the tank. The water column supports only a tiny percentage of the bacteria.
What are your water parameters at this point? Specifically your Ammonia, Nitrite and Nitrate levels?