If you download apps from the Google Play store (about 200 million apps were downloaded last year), you know it's pretty easy. You search for one on your Google Search app, and then the app you're looking for is the first entry in its search results.
When you click on the link, it takes you to the Google Play store. From there, click on Install and you're done.
While that's easy, it appears that Google's about to make finding and installing apps even easier. It works this way. Search for an app in your Google app, as you normally do.
But, instead of being redirected to Google Play, you'll see the Accept button right on your search results. (See photo below.) Click on that, and it takes you to Install.
You can check for yourself if you have this new Google feature. On your mobile device, click on the Google app. Search for a specific app. If it takes you directly to Accept, then Install, you've got it. If not, you probably will have it soon.