The MPLAB® Xpress IDE needs a program called MPLAB Xpress USB Bridge to connect MPLAB Xpress IDE to your local USB port. This allows MPLAB Xpress IDE to send a compiled .hex file to a Curiosity board with integrated programmer or a development board connected through a PICkit 3 programmer. The first time you launch the programmer, MPLAB Xpress will open a window as shown in Figure 1. You can then download the Java runtime app if you don't have it installed. Launch the bridge tool by clicking on the "Start USB Bridge Tool" button.
Run the downloaded program and the USB Bridge tool will start and make a connection to the development board. The first time you run it you will have to enter the Token shown in Step 3 of Figure 1.
When the connection is successful you will see a screen (Figure 3) that needs to stay open while using MPLAB Xpress with the development tool/board.
How To Use The Bridge Tool Video
This video shows how use the Bridge Tool in MPLAB® Xpress.