Hello,
I would like to have help setting up Dot x1 with a radius server built-in into Mikrotik. What I'm trying to do is to connect a wifi router to ethernet port of mikrotik and have EAP authentication username and password when connecting to the wifi network. I couldn't find any tutorials. I read the Dot x1 documentation on the Mikrotik site but I don't understand very well.

802.1x is aimed to connecting end devices such as computers to electrical/optical Ethernet ports. The device must authenticate before the port gets open for normal traffic, and the port setup may accommodate to that device's profile. So in your case, the WiFi router would authenticate itself, not the individual wireless clients connecting to it. Wireless clients use the same authentication method (EAP), often called WPA(2)-enterprise, like 802.1x does on Ethernet.

What is worse - Mikrotik's embedded RADIUS server, the "User Manager", supports EAP only in the 7.x version which is still in beta testing phase.

Okay. It's understood. if i choose to go with beta 7 (it doesn't bother me at all) can you help me with commands to complete the configuration?

Currently not, because I haven't given a try to 7.0 yet.

There is one post about the new user manager and using Radius for EAP.
viewtopic.php?f=1&t=185562&p=788972

So far 7.0beta5 did not work for Windows clients. It works OK for other devoces Android at least.