Hit the 'trade' button from the home page:
(To setup a recurring trade, please click here.)
Select the 'One-time only' option:
Tap the arrow between the two currencies to choose which currency you wish to exchange from.
In this example, we will be exchanging GBP to BTC.
You can see your total balance available of both currencies before making a trade (£49.00 and 0.02820783 BTC).
Enter the amount on the left hand side and it will automatically calculate the amount on the right hand side. In this case, we entered £25.00 on the left and we would receive 58,970 sats (0.00058970 BTC).
The fee (1%) and exchange rate (1 BTC / £41,970.15) are in the bottom left and right hand corners respectively.
Swipe the trade button right when you have entered in the amount.
If you would like to trade in the other direction, hit the '<->' button in the middle of the screen to move from BTC to GBP/EUR.