Hat Wont connect to Rig [Blender]

Hello, I have been making graphic design for many years, and I just figured out how to make it pose,
around 15 months ago, I had been mastering and experimenting with lights, and effects.
But there is one problem, when I pose the rig, the accessories wont connect with the rig.
Sorry if this sounds weird, but I tried to drag it in, tried to copy and paste it inside, none of them worked.
Can anyone teach me how to connect accessories to the rig?

The rig I am using is something you might already recognize when I say it
The rig is paintrig V3
Thank you for reading!

Click on the hat first and then click on the head while holding shift and then press Ctrl+P to make 'em connect. press enter and you’re done. (You should only use pose mode at this point.)

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