I have tried acid, assist and stick
ACID only tells you what firmware version you have - it won't configure CHDK on your SD card. Assist is for something called SDM - not CHDK. STICK should work for you though.
and eventually manually prepared the SD card abd put the CHDK files on it.
You will need to tell us exactly what you did here in detail if we are going to help. Did you unzip the CHDK distribution (expanding folders) into the top level folder in the card?
Perhaps it is a windows 10 issue but these aids never worked properly.
Windows 10 works fine - I've used STICK on my Win10 machine to load a CHDK card for my two SX50hs cameras many times. You need to run the
stickx.cmd file though - the other files in the installation will not work for you.
STICK creates a log file when you run it - can you post that? It would also be useful to know details about what you did and saw when you tried to use STICK?
Now I am trying to use CHDK. I start by pressing the playback but noting I can do gets me to the update firmware prompt.
Are you pressing Playback to start the camera (not the On/Off button)? Is there a file called ps.fi2 in the top level folder on your SD card?
I have looked for specific tutorial but no luck. I must be doing something wrong but what?
Every know method of installing CHDK is documented here :
Prepare your SD cardI'm getting cautious about providing that link. Too many newbies find the breadth of content intimidating, complain about the writing (mine), and threaten to write a much easier to follow set of instructions that work for all cameras and computers. I'm still waiting for that.