Sort of missing tab in spritekit layout

Im learning to use spritekit, first-project kind of newbie, and on various tutorials I've seen that there is a tab on the right column, on the bottom, with a menu that helps import visual assets quickly into a gamescene.

Upon creating my first project I can't seem to find this tab nor a way to add it to my project; under the "Custom shader uniforms" my right-most column seems empty, unlike what I've seen on tutorials. Since this 'tab' doesn't seem to have a title I'm unsure of what I'm even looking for!

This is how my new spritekit scene looks like:

This is a screenshot from a tutorial where an asset importer kind of tab can be seen:

Any help is very much appreciated!!!

Sort of missing tab in spritekit layout
 
 
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