NOTE: This tutorial is targeted specifically for the Flymaster GPS SD+ vario and XCSoar app, although the general route creation workflow is applicable to any device or app with due adaption.
Switch on your Flymaster device and connect it to the computer
Launch GSPDump
Click on 'File'->'Open wpts.'
Select the file you exported from XC Planner
A new dialog appears with all the WPs. You can edit each WP by clicking in the ID and selecting 'Edit'->'Edit waypoint'
When you are done editing, you can upload the route to the Flymaster device by selecting all WPs and going to 'Write Wpts'->'Send to Flymaster (ID + Name)'
Import the route into xcsoar app
Connect your device with XCSoar to your PC
Using the PC explorer, look for the folder XCSoarAppData in the device where XCSoar is installed
Copy the file downloaded from XC Planner into this folder
In XCSoar app, tap the following: 'Nav' -> 'Task' -> 'Manage' -> 'Browse' -> Select task file -> 'Load'