The feature is automated - so generally you do not need to do anything, however, if you would like to move the current Active Claim amount to the Ready to Claim tab in order to then perform a manual submission, all you need to do is:

From Financial > Gift Aid > Active Claim, click on the button to the right of the Active Claim screen that says 'Move Claim to Ready'. This will then move your Active Claim to the Ready to Claim tab.

If you can not see this, then your Gift Aid settings are not set to Submit Gift Aid Claims to HMRC as per Gift Aid - Getting Started