Are you trying to edit a desktop flow or a cloud flow? This forum is for desktop flows only. If you have a question related to cloud flows, they belong on a different forum here: https://powerusers.microsoft.com/t5/Building-Flows/bd-p/BuildingFlows
If it is a desktop flow you are trying to edit, you need to do it via the Power Automate Desktop app. It needs to be installed on your machine for you to be able to edit it. You can download it from the Microsoft Store, or the portal that you've shown in your screenshot, if you navigate to "Create" and then click on the Install button on the top right:

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