The first thing you need to know about templates is that when create a web dashboard (which you do in the template view) then every device based on that template.
When you create a device from the template and create a mobile dashboard, then this dashboard layout is the same for each device too.
It’s just the data that you see for each device that varies, the dashboard layout is identical.
So, if you have one device to open your garage door and another to control your heating, then you’ll need different templates, because you’ll need different dashboards.
You dont need to use all of your datastreams so you could have extra ones that do different things for different devices, but if you want different dashboards then you’ll need different templates anyway. If you’re not careful, you’ll run out of templates.
This is made worse because you can’t easily bridge data from one device to another, and use a single dashboard with tabs to do everything you want.
Node-Red makes the bridging easy though, so personally I have one main template /device with tabs that does virtually everything.
Also, when you design your web dashboard in the template view it will show made-up data, and this will almost certainly confuse you, so take care to swap over to device view to see your real data.
Pete.