Thanks for trying it out! To edit a card, click the card on the board to open the card. Then you can click the title to edit it. Milestones and labels can be changed from the sidebar by clicking the gear or heading. At the moment you can't edit the initial comment with the card but we should have that fixed soon.

I'm not sure what you mean by your second question. On Zube, the In Review doesn't have a concrete meaning, that is, it doesn't affect the card's state beyond who the issue is assigned to. At Zube, we use the Review column for cards that we have completed but still need to test, have code reviewed or just want to keep an eye for unknown bugs.