Where do I put a downloaded .amxd MaxForLive (M4L) device file in Ableton Live?
This blog should answer some questions like these: How do you install a MaxForLive plug-in? What do you do with a .amxd file? Where do you put MaxForLive plug-in files? Many MaxForLive (M4L) devices/plug-ins can be downloaded from the MaxForLive.com web-site, and many other places on the Internet.
http://blog.synthesizerwriter.com/2017/12/where-do-i-put-downloaded-amxd.html