If you've never done wheel truing before and the wheel was pretty straight before the broke the spoke, I'd suggest that you mark the new spoke with a piece of tape when you install it. Then turn the nipple on just that spoke until it is under the same tension as the other spokes and the wheel is as good as you can make it. If that's pretty good, you could stop there. If not, continue truing using all the spokes, but don't turn anything more that 1/4 turn at once. Beware that you could throw off the dish if you get too aggressive at this point, and without a dishing tool you won't know how much it's off.