Bowing is a technique best learned from a teacher. Also, proper rosin and the application of same is crucial for good tone and easier starting of the string.
Do yourself a favor and take a few lessons to get launched with the proper techniques so you won't establish poor habits.
Some information you may find helpful is on the Bass Pedagogy page, one of the first links in the first secion of my Double Bass Links page at
http://www.gollihur.com/kkbass/basslink.html