Create Smart Object Mockup Photoshop. All subsequent chapters will either be more customizability or eye candy to make the mockup more realistic. Notice that going inside the smart object is a lot like being in a new document.
You can replace the designs by right clicking the smart object layer and choosing edit contents then inserting your new image and saving the document. Knowing how to use smart objects in photoshop means you are no longer limited to using stock photography or buying expensive mockup kits. You can do the same from layer smart objects convert to smart object.
Smart objects are a very powerful.
Placeit is a great option for this because of the wide variety of their mockup catalog. Now you can resize the smart object to fit the width of the desktop screen. Make right click on that layer and choose to convert to smart object. In my case the smart object opened like this.