It is known that when you want to download the Google products on your computer than it willfirst of all download the small software that will only download and install the Google software that you wanted.
Now I will tell you How to get the Official Google Earth setup file for Future Use. If you just download the Google earth software, the computer has to be online so that it can download the real Google earth software, at first it just downloads the small software that download the Google earth software and install it.
Go the link below.
Download | Google Earth
After clicking on the link above, you will see something like in the picture below.
First of all uncheck the box for Include Google Chrome, a fast, free browser made for the modern web. Now click on the advanced setup. You will see some extra options.
Here uncheck Allow Google Earth to automatically install recommended updates select those other options that you would like to choose, then click Agree and Download. It will download the real setup file for the Google Earth that you can install afterwards without internet.