You don’t need to build it yourself. There is a browser extension (FIT Exporter for non-Wahoo Devices / RGT) which allows you to export workouts into FIT file format. You can use a FIT to ZWO converter (Workout converters | What's on Zwift?) to turn it into a ZWO and drop it into the Zwift workouts directory. It requires a bit of work, but it’s easier than building it yourself. You may be able to import into TP in some way and do it that way, but I have no experience in that area.
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