When you went through program set up, you would have elected a weigh-in day. On this day each week you can weigh-in.
To Weigh In:
Firstly, go to Tracker > Weight Tracker.
As shown above, ensure that you are on the correct date to weigh-in. Underneath that, you can then log your current weight to weigh-in.
Once you add the weight, press "save". This will take you to the screen below where it will state "weight saved". You can then refresh the page to check your new weight stats.
Below your progress graph, you can see a record of all previous weigh-ins.
To Change Your Weigh-in Day:
Firstly, to change your weigh-in day, go to settings > preferences > weight preferences.
The box on the right hand side shown below is your weigh-in day, click the drop down box to select a day, then press "save".
You will then be notified that this has successfully been changed.