Click on 'Explore' and then click on TESTME token to open its page, or open directly the token TESTME page. For Zeko, use this link
Click on 'Trade' button or scroll down to 'Orderbook' section
Select the offer you want to buy and enter the amount you want to buy
Click on Buy TESTME, sign the transaction, and wait for transaction to be included in a block
Reload page to refresh the orderbook, you will see that the amount of the offer you bought has been decreased
Congratulations! You have bought TESTME!
Now you can sell TESTME by choosing the bid, clicking on 'Sell TESTME' button and following the same steps as above, or you can create an offer or bid by clicking on Offer or Bid buttons and entering price and amount.
You can also cancel an offer or bid by clicking on the Withdraw button