Note: PhotoSpring is not officially supported on the iPad. So if you are successful in downloading the app for your iPad you will notice that it is built for iPhones.
Step 1: Open up the App Store on your iPad.
Step 2: Search for "PhotoSpring" in the search box at the top of the screen.
Most likely this will result in zero results. Have no fear, this is because of the filtering that automatically happens.
Step 3: Change the filters on the top of the screen. Change :"iPad Only" to "iPhone Only"
Step 4: This will reveal the PhotoSpring app for iPhone. Install it.
Step 5: Open the PhotoSpring app and follow instructions for Signing Up or Logging In