XMP profiles are activated in the bios under the RAM settings
Hit Del/F2/F12 depending on your board.
Head out to memory profiles page or something like overclock (because XMP is considered just that), or search D.O.C.P.
Enable hit and let it reboot, if all goes well just confirm it on Windows Task Manager.
If you get stuck on a boot loop, you may have to loosen up the timings, dialing up/down voltage or settle with a lower XMP profile. Ryzen IMC can be picky sometimes.
I had my share (and still do) of problems and the only thing I had to do to mitigate was decreasing voltage by a notch.
Check your board QVL, its not mandatory but you may want to look into it.