Yes, Xert can estimate your signature over time as you gather weeks of new data especially if any workouts include BT (breakthrough) events.
You can also seed your signature by entering known best efforts under Power Curve & Calculator on the sidebar menu of XO (xertonline.com).
You don’t need to have a “correct” signature to start with. As long as you are in the right ballpark you can move forward from there.
XATA is based on a 7 day rolling average so the pacer needle won’t come into play until you have accumulated 7 days of data to compare wiith last week.
The needle position is relative to the TL (training load) goal you have established by setting an IR (improvement rate). That’s also dependent on your starting weekly hours which in your case will be established during your first 7 days. For example, you might start at 4-6 hours/week, 3-5 days/week then increase TL over time depending on your schedule and commitment.
The Android Beta app will have the latest features for testing, but the iOS app will work fine for you too.
Lots of beginner questions are answered in this thread –
Beginner questions - Support - Xert Community Forum (xertonline.com)
You are welcome to post your profile bio here (the twenty questions) so we can tailor any responses to your requirements.
Welcome aboard. Enjoy the ride!