I am the administrator but when I try to install I get a message telling me I do not have the rights to install and to check with my administrator. I am the only person who uses this machine.
I assume you are on Windows. And on Windows having administrative privileges does not mean you already have all permissions, but means you can use the administrative privilege to gain (almost) all permissions by yourself. Let’s make an example: If there is a Windows security mechanism (Antivirus, Permission setting, Ransomware protection) to prevent from installing into a directory, then an ordinary user is lost, but the user having administrative privileges (who is also affected by the security mechanism) has the privilege to disable the security mechanism and to gain permission to install into the related directory. In that sense you need to separate “privilege” from “permission” and being a member of the administrative group or being Administrator (which generally is a locked account on Windows) provides “privileges” but not necessarily all “permissions by default”.
Having said this: Your real problem is to find the security mechanism blocking installation.
Check Start Menu > Settings > Apps > Apps & Features > Choose where to get apps and ensure it says Anywhere