I had quite a bit of frustration pairing with a couple of my machines (Mac OS X El Cap, and Chromebook). I believe that the root cause is a poorly designed BT pairing experience on the respective OSs and not the fault of any keyboard manufacturer, including WayTools.
Mice and audio devices don't require code entry. Those comprise the bulk of my recent experience and have shaped my opinion of how easy it should be to pair a keyboard.
Unfortunately, BT pairing with keyboards can be pretty flaky. You generally need to enter a code. In the past, I've been treated to a display on the screen showing the numbers to type and that display has updated on every digit key-press. That lets me know that everything is proceeding well.
In my recent experience, there was no visual feedback while entering the pairing codes which led me to believe that I didn't really have a connection. In one case, my left key-blade wasn't mated to the space blade, but otherwise, the problem was the lack of feedback during pairing that conflicted with my expectations.
Advice: locate a traditional BT keyboard and try pairing it with all your devices in order to set your expectations properly. If it has been a long time since you've paired a BT keyboard, do it again to reset your expectations.
Note: I'm told that while pairing, the TB is in numeric shift mode by default.