How do i transfer an app that has been downloaded to the PC iTunes Store to my iPhone 5?

How do i transfer an app that has been downloaded to the PC iTunes Store
to my iPhone 5?

I downloaded Real Racing from PC iTunes Store.
How do I transfer it to my iPhone? I see a Cloud sign in in the app on the
iPhone but when I press it, it asks me to be connected to WiFi but I don't
have a WiFi connection but mobile data is available.