Learning Path FreeRadius

Good Day all, With my recent venture into setting up a RADIUS server using freeRadius. i have discovered there's a lot i don't know about the capabilities and setup of freeRadius, Please can anyone point me in the direction of useful learning material on more advanced setup like the setup of realms, unlang and the likes and also materials on scaling too. I have read the beginners installation guide. Please any help would be greatly appreciated. Best Regards Uchenna Nebedum