Go to the JNB website (jnb.com), Click [Login] from the menu and enter your details to log in.
If you want to purchase BTC with ETH, choose ETH Market and input BTC in search box or click BTC/ETH pair, as shown below.Then you can enter to transaction page, as shown below.
Enter the buy area of the Basic or Advanced website, refer to the token/coin price on the left, choose a right sale price of BTC and enter the number, click the button of the “Buy BTC”, then you can finish your purchase. (Sell BTC is the same as Buy BTC)
default price of order area is the last transaction price. You can choose a market price if you want to make a transaction quickly.
If the market price of BTC/ETH is 0.2 but you want to buy in 0.1, then you can choose the Limit Price.
The “25%” below amount means to buy BTC with your 25% ETH balance(same as other percentage)