It's pretty easy, you just need to make a new account that's not associated with identifying information from your banned account. Use a different browser, preferably one that's focused on privacy like DuckDuckGo or Brave's browser to avoid something called fingerprinting, and don't use the same IP address. Rebooting your phone/ router or using a different wifi network usually works. Obviously don't use the same email either.

Now when you start posting, if this didn't work, you'll be shadowbanned. It will look like you can use reddit, but nobody will see what you write. You can plug your name into Reveddit.com to check after you've commented or posted. If you're shadowbanned you'll see this message: [user_name] may be shadowbanned or may not exist. Verify the url and reload this page to double check. You can also check account status at /u/[user_name] or /r/ShadowBan.