Reset password does not work

So I'm trying to change my password for my ownCloud server. The problem is I'm not getting the reset link on my email.

I looked this up and it says that I need to run a bunch of commands. The problem is I don't know where I should run them on. I am very new to backend so any help would be appreciated. Thanks!

I did that in the past by following the documentation https://doc.owncloud.org/server/10.0/admin_manual/configuration/user/reset_admin_password.html