When you first sign up to Community, we will register an account associated with your Apple ID using Sign in with Apple. As such, regardless of the device you are using, Community will log you in based on said Apple ID. For example, if you were to take your device and log into a friend's Apple ID, this would mean that the next time you use Community, you would log in under your friend's Community account.
As such, it is not possible for our Community members to make multiple Community accounts under the same Apple ID. The only way you could make a second Community account is by logging in under a different Apple ID.
We would generally recommend that you only use one Community account, as it ensures that your classmates can more easily find you to share study materials.