First, Install the App on your phone, either from the Apple App Store or Google Play depending on what kind of phone you use. Examples here are from an iPhone

After installing, launch the app and you will be asked for your phone number.

A code will be sent to your phone. Enter it on the next screen

You will then be asked for an account to link. Make sure that you use a debit card here, as it will not work for a credit card.

You can ignore this next screen. Touch the X in the upper right corner to get rid of it.

Now you will be at the payment screen. This is the screen that will open up each time you launch the app.

To pay someone, just put in the amount you want and touch the Pay button. You will get a screen that will allow you to specify who to pay, and also an option to enter a note. In the Example below, I already had EHRC Treasurer in my list. The first time you pay a fine :-) you will need to enter $EastHartfordRotary