Adding custom lovelace cards to dwains dashboard

Hello everyone,

I have a question regarding adding custom lovelace cards to dwains dashboard. The documentation does mention page addons. But im not sure if that is what im looking for. I essentially want this thermostat card: GitHub - ciotlosm/lovelace-thermostat-dark-card: 🌡 Thermostat card with a round and black feel to it

to show up in dwains dashboard in the thermostatmenu:

and if possible, i would like to have these other cards removed. (sorry for the weird screenshot. i could only upload 1 file. So i had to be creative)

many thanks for the help!