: Double-click the thumbnail of that layer. It will open a new tab. Paste your logo (preferably a transparent PNG) into this new tab.
: Look for a layer often named "[YOUR LOGO HERE]" or "Place Design Here." This is a Smart Object layer.
: This specific mockup is also available through Creative Fabrica for users with a subscription or for individual purchase.
If you don't have Photoshop, you can use browser-based tools: Free paper mockup generator - Canva