If you're already paying taxes with your full or part time job and you tend to get a refund, you may not need to pay quarterly taxes. On the other hand, if you usually break even when you file your return, then it might be a good idea to make those payments.
I would recommend filling out Form 1040-ES here anyway to find out for sure. This will essentially compare your full time job to your self employment work and help determine whether you need to submit quarterly payments. It's a little extra time and math, but will ultimately give you the best answer!
Stride has whipped up a step by step guide for filling out Form 1040-ES here -> How do I file estimated quarterly taxes?
If it turns out you do owe quarterly taxes, you can find instructions on how to get started here.