Installation of gnucash 2.6.18

[Gary Davidson]

I have apple system Yosemite 10.10.5 and downloaded gnucash 2.6.18.  When
the icon was downloaded onto my desktop what do I do with it to have the
program in my applications.  (Mac 10.5,Intel. and PC) were shown but only
Intel and PC could be chosen.  Can anyone help me with the proper steps to
move the program into my applications?
Thank you for any help.
Gary