I’ve just now used the above linked Broadlink Manager… There are very few instructions so hopefully this is helpful for someone…
The context to this is a brand new RM Mini 3.
The first thing you want to do is get your device paired. You will need to connect your computer to the wifi network BroadlinkProv. I wasted a lot of time not seeing the network, before deciding to reset the device. After resetting, I immediately saw the network appear.
Connect to that network and hit the ‘Add Device’ button (if we’re honest, I had hit add device BEFORE connecting to the wifi network).
From there, I think I populated the 3 middle boxes, the wifi network I wanted it to go onto, the security mode, and password. I read somewhere on Reddit that it can only be connected to 2.4ghz, but I don’t know that for certain.
Then hit pair!
I think at that point I rejoined my wifi network that I had just added it to, and ‘Rescan wifi’. Then seeing it appear, hit the ‘Add to Devices List’ button.
Exit the add device screen and scan for devices and hopefully it appears for you 
Hopefully that helps someone… the learn command and send command functionality seems to work pretty well from a quick play around, and is fairly straightforward.