First, Please post your full DTH code, preferrably a link to your code in github so we can see the whole thing.
Second - customizing the UI (or ‘device presentation’ has COMPLETELY changed since classic. Most of the stuff in the DTH - especially the items relating to TILES doesn’t do anything at all anymore. Without Custom Capabilities and Custom Presentations for those capabilities producing a VID which you can then implant in your DTH - you wont be able to make many UI changes at all. Learn more here: Custom Capability and CLI Developer Preview - Developer Programs / Tutorials - SmartThings Community
That said, why write a DTH - what device are you trying to setup exactly and what led you down the path of needing a new DTH?