creating a clipping mask by pressing ALT on the top layer does not work

This is yet another "I saw someone do this but for some reason it does not work when i do it"

I'm trying to create a clipping mask. The guide says "create a clipping mask by holding alt/option, and wait for this little arrow to come down"

When i hold alt nothing happens, when I try to drag it towards the layer below, the cursor changes to a plus, and all it does is duplicate the layer.

This is what I'm trying to get: (cursor changes to arrow icon)

layers appear staggered and not directly on top of eachother or in the same layer:

thank you in advance!