How to put an app on my iPhone after it's installed

The only way I can access it is to go to the Apple Apps application and search for it every time.

Your retaded

It should have been on your Home screen immediately when you download and install it.
Try searching your Home screen and see if the app is there. It should be there.

Whenever in the app store, if the apps says "Installed " it means that the particular app is on your device. You can find the app without having to go to the app store. Just place it in a place where you believe is the easiest access for you. Like first page on homescreen