Replacement of driver side mirror

Any advise on how to replace a driver side mirror on a 1997 328IS - I think a biker must have hit mine and broke it off? I purchased a replacement
driver sidemirror WITH NO INTERNAL MOTOR OR MIRROR so I also need to know how to swap the original glass mirror and motor from my damaged mirror.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.