To record a weight, sign in to your account, then scroll down to the registrations panel.
Now, click the desired registration name to open the registration popup:
Once you see the registration popup, change to the weights tab:
The weights tab will list all existing weights including the average daily gain (ADG) between each weight.
From here, you can record a new weight by entering the observation date, the observation value, and then press the
"Tick" button to save the record: