You want to put the 3dsimport.mll in your plugin folder. You'll find a bin folder inside your main program folder and a plugin folder inside of that bin folder. All your plugins are in there...a lot of the Mayan architecture is based on plugins....so place that file there. Next open Maya and go to Window/ Settings/Preferences/ Plugin Manager...now find the 3dsimport plugin and load it. If you want it loaded automatically each time you open Maya check auto load as well Now when you want to import a .3ds that format will show up in the File Browser as a choice

Darkon