If you have admin rights then fo to "System (top right)" and then search for "External System Import" and then select CSV.
Shortcut for this is just press "g" twice in quick succession and type "external system import"
If you don't have admin rights then on the top banner you would be seeing "Issue", when you click on Issues there would be a list of options displayed and one of them would be "Import issues from CSV" but this option is a scaled down version of "external system import"
Tarun is right on how you do this. But I will try to make a step-by-step for you.
Hope it helps you.
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