You can add new customers from a few different places. The most accessible is the button from the top left.
If you are on a mobile phone, your screen will be zoomed up and your menu minimized. You can just click on the menu to expand it and access the Add Customer button.
Another option is to add new customers from the View/Add screen by clicking anywhere on the route on an open spot.
You can also add customer from leads--Customers->Leads->View All
Customers->Leads->Map. Click on the property of the new customer and you will get a pop up window.
