How to Rosin a Violin Bow for the First Time
A new violin bow may not have any rosin. If you use it to play it will not make any sound. You need to put enough rosin on your bow to make a layer of powdery rosin over the full length of the bow hair.
There are a few kinds of rosin out there, but I would not worry too much about the type if you are a beginner violin player. Your violin probably came with fine rosin anyway, so use the rosin you have.
You need to really dig your rosin into your violin bow. If it is the first rosin to go on your bow then you may need to really work at it. Keep rubbing the rosin on the violin bow hair until it is covered with a white powder. They may take several minutes the first time.
You can place your thumb on over the mental piece of the bow frog so you do not tap your rosin on it. If you do tap it then your rosin will crack! Your thumb will protect it.
Everyday you practice your violin you need to put some rosin on the bow hair. 10 or so passes up and down the violin bow should do it. You be the judge as you play. If you feel like it is too much rosin then next time you can do less.