In order to use SpellBox, you need a license key available here: https://spellbox.app.
Once you have obtained your license key, simply download and install the extension in your favorite JetBrain IDE.
Here is a quick video below on how to authenticate in your JetBrain IDE.
You will be asked to open the site https://spellbox.app/licenses-manager to view your license key and e-mail.
Once you have those, simply enter them when prompted.
And that's it! You're good to go!