If the automatic sync between Suunto App and PowerCenter did not work, you can still get your data into PowerCenter (as long as Stryd was used and the watch recorded the power data). Note that you can only import data using PowerCenter on your computer, it is not possible with the phone app at this time:
Open up the Suunto App on your phone and select the run you want to export.
Select the three vertical dots on the top right, and select "Download FIT file".
This will save the FIT file to your phone (typically, the file will be stored in the download folder on your phone). You then need to transfer that FIT file to your computer. There are many ways to do this, for example, you can email the file to yourself.
As a final step, import data into PowerCenter.
Go to your PowerCenter Calendar https://www.stryd.com/powercenter/athletes/calendar
Select the up arrow in the top right corner
Select Upload Run and follow the instructions on the screen.
Note: You can import FIT and TCX files into PowerCenter. This can be helpful when using a Polar V800 watch, or when manipulating FIT files. TCX files exported from Garmin Connect cannot be imported as they lack power data.