The question of how much rosin to use is a common one amongst adult beginners. There is a lot of stress about it.... "Did I rosin too much?" "Is my rosin too old?" "Is my rosin working? "I'm squeaking....therefore I NEED more rosin!!"
Okay, let's stop stressing and break this down...
As a beginner, best thing to do: get in the habit of rosining every day for 15 seconds. That's all you need to do, simple.
Rosin is the sticky stuff that dancers put on their feet and gymnasts put on their hands to keep from slipping. Putting rosin on the bow functions in the same way - you keep your bow from slipping but also, you have enough friction to get the string vibrating.
If your bow has NO rosin it will not be able to pull the string to make a sound. If your bow has too much rosin then your sound will be a little gritty. But, like I said before, don't stress. Just take your cleaning cloth and wipe your bow once or twice to remove excess rosin if you have too much.
How do you know if you have too much? You will see a dust cloud come off your strings when you play.
The important thing is to stop blaming rosin for less than desirable tones/sounds coming out of your instrument. Most squeaks are "user error" and cannot be blamed on rosin. Rosin is innocent:)
Other rosin truths: