Sharing & permissions settings problems Sonoma 14.4, only have one user

Very Basic Goal: to create new folders, and drag and drop folders onto my hard drive. (new 2023 iMac, M3, running Sonoma 14.4)

My computer is not now, or ever will be, networked, I am the only user and administrator.

Problem: Hit command-I the hard drive icon, where sharing & permissions is shown (see screen shot). I clicked the lock to unlock it. I tried adding a user and selecting my name, but it denied me permission. It also denied me permission to try and make changes to "wheel" (what is "wheel" anyway?) or "everyone" to try and get read & write in any category, but same result, "The operation can't be completed because you don't have the necessary permission".

Feeling insanely helpless as I've been using Macs since Forever and dragging and dropping folders or command-N to create new folders is not something I've ever had a problem doing.

Currently stuck putting all my files on the desktop which is rapidly becoming a Flustercluck.

Help!

Part Two of this Question would be, if I don't have plans to ever have anyone other than me working on this computer, is there anyway to stop the endless entry of administrator password every time I want to complete an action, or will I be changing permissions app by app?

Thanks in advance for your help.