It can be pretty much transparent to you. For the most part it will be behind the scenes. Smart things is updating the hub drivers and device drivers to the new edge format. During the process some of your devices may have problems.
If you read various posts here, you will find that some folks have created new edge drivers for various devices. They can be installed if you do not wish to wait. That is what I have done. However, most of my switches have already converted and I have added maybe three other drivers from folks.
Read the postings and you will find out how to identify your driver status as well as how to add the custom drivers.
The official plan is that all the transitions will happen behind the scenes, and users won’t have to do anything. However, the road has been bumpier than that so far. 
. Some of the new official edge drivers have bugs, or are missing features, so quite a few power users, including the people who typically read this forum, are using custom edge drivers instead.
If you want to know more about the details, see the community FAQ:
FAQ: I have no idea what Edge is. Is that a new developer tool? (2022)
Otherwise, you can just wait and hope you’re one of the lucky ones and everything happens automatically without you even noticing.
Progress continues to be made on the auto migration of devices to edge drivers. As of this morning I’m down to 8 devices that have not yet migrated:
6 - NuTone NWD500Z Smart Z-Wave Enabled Wall Dimmer Switch
1 - Zigbee Switch, Inle Smart Light Switch
1 - Enbrighten Z-Wave Plus Smart Outdoor Switch, 1-Outlet Plug-In (2nd Gen.)
Still have my fingers crossed that eventually they will all get auto migrated.
I’ve had one of my Kwikset 916 locks migrate but the other 916 and 914 haven’t. The one that migrated and the two that didn’t had the “Z wave lock” DTH’s. Odd one would migrate and the other two didn’t.
There doesn’t seem to be any perceivable pattern to devices migrating. Others have reported similar behavior where some of their devices of the same type migrated and others did not.
I guess the question would be should one attempt to force the new edge driver to those like devices that have not yet migrated for some reason?
Only if you’re in a hurry to get them over to Edge, and willing to rebuild any automations that will be destroyed when you exclude and re-add the devices. In my mind, if one device has migrated, the rest will likely follow before too long, and as long as you aren’t suffering from DTHs that are losing functionality it’s not worth the trouble.
If you want to move them and not lose Routines where the lock(s) are the only device, create a virtual device as a placeholder and add it to the Routine. Then once you have removed and re-added the lock, you can swap the lock back into the Routine.
This is the exact method I used to be fully migrated over before. Yes it takes some time but it’s done and nothing is broken.
Most of my devices have migrated except
Schlage smart lock which I’d love to get local
Sonos
Lutron caseta light switches
Everything works well.
Hoping the lock gets local and we get some version of LUM back.
I’d suggest migrating your Schlage lock to the [ST EDGE] Z-Wave Lock PH - Devices & Integrations / Community Created Device Types - SmartThings Community from @philh30. It exposes many more settings than the stock Edge driver and fixes several bugs as well. Also, the beta version of the driver in the same channel adds the capability to see how/who unlocked the lock on the device panel as well as making that a trigger for Routines. Since you can trigger on different lock code names with this capability, it offers the ability to do per lock code actions similar to what LUM previously offered and will run locally.
There is also a Sonos driver in the ST beta channel that offers some basic Sonos management features.
I’m getting a bad link when I check that out
Should be fixed now.
I had one of each device type migrate and the one device that had previously migrated actually revert back - with drivers showing in hub device properties in the app. The easiest way to keep things consistent was to remove the devices (taking steps to not lose any routines) and then re-add them. Devices not yet showing as Placeholder are Hue and Sonos.
The Sonos driver for Edge isn’t quite ready for prime-time. It’s quirky and several commands don’t function as intended. SmartThings is working on it, but I’d be patient with that one.
Use EDGE driver， Does device will be executing locally？
yes, all Edge drivers run locally on the hub
so it appears Edge drivers take precedence over Groovy DTH including custom when pairing devices.
I asked @nayelyz to check on this two weeks ago because we are seeing reports both ways in the forum now. Some people saying they had to delete a custom groovy DTH before the edge driver was accepted and others saying they didn’t.
I am starting to wonder if maybe it varies by model number now, but I just don’t know. Or maybe there’s even a flag on individual accounts for specific devices that have been automatically migrated. It still feels confusing.
@JDRoberts And, the precedence actually switched for me from DTH precedence to Edge Driver precedence over the last few weeks. (for a Quirky Tripper from Sercomm (originally on Wink) )- so a pretty old/ now uncommon device).
It could be, and likely is, a complete coincidence, but I had my first ‘significant’ migration happen in the same period. (about a third of my Commercial Electric tunable downlights switched over) - just thought I’d mention it - it could be hub-specific. (I’m on V2, FWIW).
[CORRECTION - upon review I think that installing a custom driver with the exact fingerprint is what caused the ‘change in behavior’ - sorry about any confusion!]