Assuming you're talking about online chess (not live chess), then click online chess. Then you will see your current games. Below you will see the challenges you have encountered. You need to click on the view to find the one you want to accept and then accept. Of course, you can't have any challenge. In that case, you can go to online chess and look in the upper right corner of the screen. You will be looking for a link called Open Seeks. Click on this and you will see some common challenges that people are looking for partners. Look at them and accept them in the same way you would accept your challenge.
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