The Samsung Pay app works a little different than most other apps. The first time you open Samsung Pay, you will be given information on how to use it and be asked to put in your credit card information (in a very convenient way, by the way) and asked all kinds of permissions and agreements.
Once you have given all this information, Samsung Pay waits patiently at the bottom of your home pages, ready to meet your payment needs with nothing more than a quick swipe from the bottom of the screen. Most people would simply not use this app if they had to go digging through their screens to find the app. This way, you do not have to search to find the app and wait for it to come up.
The following figure shows the Home screen with the Samsung Pay launch button sitting at the bottom ready to appear with a quick flick.