One tap, one order
Tapping Up or Down buys at the best available price, up to your Max extra to buy (set in Controls). If the price has already moved further than that, the order is cancelled rather than left waiting, so you never pay more than you allowed.
Your Highest price setting caps what you'll ever pay per share.
Close
Close sells your shares before the round ends at the best available bid, within your Max less to close. Use it to lock in a profit or cut a loss. If no one is buying, Close is greyed out.
Swap
Swap closes your side and then buys the other side in one tap. It happens in two steps, so if the second step is blocked (for example by a daily limit), you can end up with no position.
Line orders
Draw a line on the chart and arm it to buy automatically when the price crosses it, even with the app closed. You can pair two lines so one cancels the other.
Keep filling
If only part of your order fills, the optional Keep filling setting keeps trying to complete it, never above your original price limit, for the time you choose.