You can get data from various platforms into PowerCenter. For example, data in Garmin Connect and Movescount can automatically be loaded into PowerCenter. You can also manually import data into PowerCenter from the Zwift and Polarflow platforms.
If you use a Suunto, Polar watch or Zwift, the data in PowerCenter will not be complete as the watch/Zwift do not record advanced metrics such as Ground Contact Time. In those cases, you can get the advanced metrics by uploading the data from Stryd with the Stryd app on your phone (offline sync).
The order will not make much difference, the only metric that might change is elevation (last data imported will provide elevation if applicable). We have an algorithm to merge data for the same activity. Whether your data will merge depends a bit on the source of the data:
1. Zwift, Suunto and Polar data will merge with Stryd data in most cases (sometimes our algorithm is not able to find a good match and you end up with doubles).
2. If you have a complete dataset already which contains all metrics (i.e. recorded with Garmin watch, Apple watch or Stryd app), the data will never merge and you will get duplication. You can always delete not needed duplicate data.
If you need more assistance, contact email@example.com.