Available in English version since version 1.4.2
To import data from the Strong app:
1. Open Strong app
2. Go to Settings > Export Strong Data
3. Save CSV file to your device
4. Open Fitness Logbook app
5. Go to Settings > Import Data
6. Tap on Upload CSV File and select the exported CSV file
7. Set the weight and distance units that will be used in importing
8. Tap Run Import

To import data from the Hevy app:
1. Open Heavy app
2. Go to Settings > Export & Import Data > Export Data
3. Tap Export Workouts and save CSV file your device
4. Open Fitness Logbook app
5. Go to Settings > Import Data
6. Tap on Upload CSV File and select the exported CSV file
7. Tap Run Import