Is the whole set new?
Is the sand "live" sand and new in the bag?
The color is "what you like". Look at some tanks that have black sand. planejane and omreardon have black sand and digidana will soon. It is not something that you cannot change, but you will not want to unload the whole tank to change sand color, imo.
Used sand from someone's tank can be full of toxins. I personally do not think it is a good idea to move sand. I am sure it has worked, but..... it is not for me.
Vinager and a rag (make sure a rag as free of soap as is possible is used. Rinse and clean with bleach - diluted. Rinse and use a little bit of vinager again. rinse several times. thinging again, I have never used bleach on by acrylic tanks. So, that may not be a good idea.:spin1:
Welcome to the hobby. If you are willing, you can learn something about it almost continually.:dance: