Button-card template missing - where to put?

[pliant elbow]

Trying to follow this guide (https://github.com/IDmedia/hass-unraid/tree/main) to use their UI for Unraid shares into my HASS and I've got my Unraid box communicating to entities in HA, but I'm struggling with the UI.
First screenshot is the error I'm getting when I put in the YAML into a dashboard. My YAML is the same as the github's, I only updated the entity name to mine.
Second screenshot is where I put the template YAML files (I think this is no longer how it should be done, but I haven't touched templates before).
Third screenshot is where I'm probably ultimately confused from the repo's instructions as I think I put the templates in the wrong spot, but I also don't know where to put that line to make sure button-card can find the templates.

Thanks in advance!

[potent sapphire]

Custom:button-card templates will go into the Raw YAML. To get to it, edit your dashboard, click the three dots in the upper right corner and select Raw Editor. (A word of caution: be careful because you can easily mess things up if you're not familiar with working with YAML directly. Indentation is super important.)
The template section (called button_card_templates:) will be put at the beginning before the views: section which will probably be Line 1 for you. You can take a look at my dashboard and see this, but my Line 162 will probably be your Line 1. My dashboard

If you're using a YAML-based dashboard, there are some different options available which is what I think you were trying to do but are not available in a UI-based dashboard.