How to manually change signature for activity

I am trying to seed my progression according to the FAQ. I only have power data available for the past 2 weeks and it seems like Xert is not really getting a stable image of my fitness yet. I started training about 8 weeks ago, so I think I have a good idea of where I was back then.

I created manual activities to accompany those activities I uploaded without power data. The FAQ says to save the signature in the advanced tab of the first activity, but there simply is no advanced tab. I can edit threshold power for the activity but I cannot save it. Every time I close the activity and go back, the original value is there.

How can I correctly set my initial fitness signature for those activities?

Hi Till. When you open the Activity Details page for the activity, you can open the Advanced tab. The controls for managing the signature are below the chart.

Thanks, Armando. I found it for activities that have power data available, but not for activities that have NO power data. Is it supposed to appear always?

Although, I now also have a slightly different question:
Xert estimates my total power at about 200W. I think it’s overestimating, I believe my true total power is at something like 170-180W. However, if I keep fiddling with the signatures, I can get it to estimate my total power and training load correctly, but it gets my relative efforts within the activities all wrong. If I don’t use any seeding and just let Xert do its thing, it underestimates my training load, seemingly overestimates my total power but the relative efforts within activities are SPOT ON. I have two activities from which I have a clear recollection of how I felt at certain moments in time, and the MPA graph reflects that very well.

What’s the recommended course of action here? I’m leaning towards not fiddling with the signature and hoping that training load and total power will at some point in time converge with what I believe is correct. Is that a sound strategy?