MAke sure you have a Github and Unity account setup.
Go to: education.github.com/pack
Click on Get Your pack
Sign in to github
If asked select authorise this application.
Click get benefits
Click on the Unity redeem option.
Finally click on the Activate button.
You will need to have your Github accoutn verified first, this can take a while.
You should then have access to the Unity Student plan.
Check your email for a Unity student plan licence key.
Open Unity hub
Sign into your account.
Click on manage license
Choose Unity Plus or Pro
Enter your serial key
You now have a Pro version of Unity on your student plan.