1.  Go to the Amass releases page
  2.  Right click and copy the link of the file that corresponds to your system / VM architecture (amd64 for most).
  3. Open a terminal and type "wget addressYouCopiedGoesHere"
  4. Enter "unzip FileName"
  5. Type "cd amassFolderNameGoesHere"
  6. Type "./amass"