How to install manual OS X Yosemite?

I have a Mac Book Pro Version 10.7.4 from mid 2010 and I downloaded OS X Yosemite 10.10.5 from the Apple Support page and was hoping to install it. However, it tells me that "You need Version 10.10." every time I click on the .Pkg

Has anyone else encountered this problem, and is there a trouble shoot around it. Also I cannot download it from the app store at home as I have little to no broadband.

Thank you so much in advance for any help!