How can I find out what my sudo password is on SteamOS?

I'm trying to install an app on SteamOS and it's through the Terminal. When I run the command, I need to enter my sudo password as can be seen below: --- The thing is, I’ve never set a sudo password as far as I’m aware. How can I find out what this password is, maybe change it or remove it? I really don’t know what I set my sudo password to, I have no memory of ever setting one. I found this answer , but it didn't help me as when I enter those commands, then it asks for the sudo password again which I don't have.