download and install gnucash on iMac OSX

[Eldon Fredericks]

Help! I am attempting to use gnucash on my Mac running Yosemite OS X. After downloading gnucash from the website I have placed the file:
Gnucash-Intel-2.6.5.6.dmg
in my applications folder.

Then when I open that file I am taken back to the original web site from which I downloaded the file and it eventually opens the program on my computer after warning me that I am downloading something from the web.

What have I done wrong or what more do I need to do to make this software operate on my computer without going to the website to load?

I have read various tutorial and manual pages and watched several youtube tutorials but they do not address initial installation on Mac.

Can someone help, please?

Eldon Fredericks