The owner of the edge driver channel has to give you the link to join the channel. You just follow the link, pick the drivers you want, and then they will be downloaded to your hub. This can take anywhere from a few minutes to a few hours.
Some authors will post the link in the GitHub documentation, others will tell you to get in touch through a website or email, particularly if it’s a closed channel as opposed to open for anyone.
So it just varies, and it’s up to each author to decide how they want to control channel membership.
USING A DRIVER ONCE IT HAS BEEN DOWNLOADED TO YOUR HUB
That’s just for getting the driver downloaded to your hub. Most of this thread is about what you do next, and the short answer is that when you add a device to your smartthings set up which has a fingerprint that matches that driver, then The device will automatically use that driver. You don’t have to go through any additional install steps like you used to have to go to with groovy DTHs.
DURING THE TRANSITION PHASE, CUSTOM GROOVY DTHs HAVE PRIORITY OVER ANYTHING ELSE
During the transition phase while both Groovy and edge drivers are available, if you have a custom Groovy DTH on your account that matches a new device’s fingerprint, that’s what will be used. If you want your system to use an edge driver instead, you have to either remove the Groovy DTH from your account all together, or at least modify it to comment out that particular fingerprint.
CHANGING FROM ONE DRIVER TO ANOTHER
If you have more than one driver on your hub for the same device, you can switch from one to the other by going to the device details page in the app, tapping on the three horizontal dots in the upper right corner, and then choosing “driver.” This will show you a list of the drivers already available on your hub for that particular device. Noted it does not show you the list of all possible available drivers, just the ones you’ve already downloaded that match that device.
FINDING OUT WHAT CHANNELS YOU’VE ALREADY SUBSCRIBED TO
If you need a list of the channels that you have already subscribed to, go to the device details for your smartthings hub and there should be a list of driver channels there.