Welcome to the commander format. I have been playing it regularly for several years now. I have a lot of fun with it.
For a commander deck, each card in the deck must have color-identity that is shared with the commander. Color-identity is defined as the card's color(s) plus any colored mana symbols in its text box. The full rules for commander can be found on
www.mtgcommander.net.
To put it more simply, if your commander is mono-white, then no card in your deck can have any color or mana symbol other than white. Colorless cards also have no color identity, so they are fine in a mono-white deck.
Happy Brewing