If you don’t have ssh installed, install it. (google is your friend) Then ssh firstname.lastname@example.org The board will tell you what the password is, on my it was temppwd.
To change your password use the command password it will ask you what your current password is, then ask for the replacement. Then it will say it was too simple and you have to do it again. Normal stuff.
If you want to insist on using your simple password, try this.
sudo -s (become superuser/root) enter your password password debian (put your simple password in) exit (exit from superuser/root)
When you are running as root, password is more compliant and will accept simple password