You can use directly from where it is by specifying the whole path, e.g. ~/Desktop/smultron but if want to be able to use it by just writing "smultron" in the Terminal you have to follow the steps below (note that you need an administrators password for this):

1) Choose Go to Folder... in the Go-menu in Finder
2) Write /usr/bin and press enter
3) Drag smultron from the "Smultron command-line utility"-folder to the folder that you just opened and choose Authenticate and then write the administrators username and password when asked to


If you want to view the manual by writing "man smultron" in the Terminal you have to follow the steps below as well:

1) Choose Go to Folder... in the Go-menu in Finder
2) Write /usr/share/man/man1 and press enter
3) Drag smultron.1 from the "Smultron command-line utility"-folder to the folder that you just opened and choose Authenticate and then write the administrators username and password when asked to