If there is no wind instrument on your boat that can be recorded in the boat's log file, there are 3 ways to add True Wind Direction (TWD) data to the analysis.
Even when wind data is not otherwise available or cannot be inferred, adding a fixed values for TWD can enhance the data and provide TWA and VMG estimates. Choose "Use a fixed wind direction" in the upload form.
When sailing small boats, it can often be easiest to measure true wind from off the boat, such as from a coach boat or nearby buoy. Wind data can be uploaded in any of the supported formats (select File Purpose: Wind Data in the upload form).
Use the TWD Inference feature to let the system infer True Wind Direction throughout the day. It uses maneuver angles from tacks and gybes, and will also follow wind shifts when sailing straight. Having TWD data available (even if only estimated), unlocks features such as VMG gain/loss analysis which can be performed on any part of a test or lineup.