I've lost about 12 days of earnings because I've not added my 396 HAT in the stake
Patience!
Anyhow in my opinion Hawala should realize a guide on Youtube for this staking wallet. It will be more clear.
Another question:
if I desire to transfer my 396 hat elswhere (since now they are blocked in my wallet for stake), I need to Click Cancel to remove tokens from stake...right?
You can click on the Claim button after three days period passes to earn incentive. If you click Cancel, you won't get any incentive because incentives aren't earned automatically. You have to claim it. So, if you need to move your HAT tokens elsewhere, first claim your reward and then cancel the staking. You can claim incentives after 3 days, 6 days, 9 days... Just make sure you don't claim it after for example 5 days because you'll get incentive only for the first three days period.