You will want to delete or rename your current `~/.offlineimaprc` as well, as although you can later modify the `~/.offlineimaprc` produced by the script, you must have no file there the first time you add your first account or the wizard will assume some settings are already set which aren't.
Just run `mutt-wizard.sh` and choose to add an account. After you do so, you may run `offlineimap` to begin the mailsync, and you will be able to run neomutt and see your mail.
If mutt doesn't immediately work properly run the `Redetect mailboxes` option, then open mutt. This may be necessary for some accounts.