Select appropriate forum, then appropriate sub forum.

but still cant see the "create topic button ?

To enlarge an image, right click image and choose Open link in new window.

And then scroll down to select an appropriate forum.

??? button at the top of the page is not helping me if I can't see one....

"im not the sharpest tool in the shed" but i am a tool "

That @electronic-zookeeper was up there when I clicked the Reply icon on your last post. See pic.

As to your question. Since current is drawn or pulled from the source, or even more correctly is allowed to flow then it protects the supply against a short circuit most commonly but in reality any current above the ATX design point.

I think you are over thinking it. For a set of 5V posts, add a fuse to the + post (just behind it actually) of either 500ma (USB2.0), 900ma(USB3.0) BUT if you are powering more than MCUs and/or MPUs then use a fuse that accounts for the extra draw. If you will be powering a Pi5 then allow 5A but it would be much better to use an official Pi5 wall wart for Pi5 power supplies.

What commercial bench supplies do is they have controllable voltage as well as current  but the ATX DBWS project does not have that feature. IIRC, the newer Linear supply that Bill designed does have a typical CV and CC function.

IF you are still confused, 3A is a good ball park or even as high as 5A PER set of 5V or 3.3V or even 12V posts. I use 5A in the 5V, 3A in the 3.3V and 10A in the 12V but I have 2 of each so there is a total of 6 fuse holders on the back of my supply.

Remember it's motors that need the most power, all your Micro Controllers or Micro Computers and almost all sensors only use a few 10's of ma up to a maximum of a small number of 100's of ma.