I have been through the process of setting up an instance of the nextcloud app as detailed here: https://www.opalstack.com/blog/2022/05/11/your-ultimate-google-to-nextcloud-guide/
(I just used the info on setting up the nextcloud app, not the rest of the article on linking to Google at this point.
Everything worked without a hitch but the installation process did not ask me for a user name or password, or an email address, and when I went to the app to try it out for the first time, it loaded a login page which asked for a user name and password. After trying my Opalstack account user name and password and the email that is linked to my Opalstack account, I could not logon.
I did find instructions online to reset the admin password for nextcloud, and saw that the default user name appears to be 'admin', I tried to reset the password, but got an error message saying that the version of PHP installed is too old and needs to be upgraded, and I'm not sure how to do that on Opalstack.
Any help with these problems would be greatly appreciated.