Problems Installing Teamviewer for Pi

I'm trying to install Teamviewer on my Pi5 so a friend can help me install some other software that's particularly tricky to configure. The problem is, I can't even install Teamviewer for Pi.

Following the instructions on the Teamviewer website I enter:
apt install ./teamviewer_15.58.4_arm64.deb

in the terminal, and receive the following errors:

E: Unsupported file ./teamviewer_15.58.4_arm64.deb given on commandline (that's the name of the file I downloaded)
E: Could not open lock file /var/lib/dpkg/lock-frontend - open (13: Permission denied)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?


I added "sudo" to the beginning of the command, thinking it might resolve the Permission denied error. It appears to have worked, but I still get:

Reading package lists... Done
E: Unsupported file ./teamviewer_15.58.4_arm64.deb given on commandline


Why is a file, written for Raspberry Pi, unsupported? How do I get my Pi to recognize and support it?

Any help would be gratefully received.

Ken