photography cheat sheets, anyone who can explain

They appear to be just a quick guide for that particular camera model. I would try to decide the camera you want first before looking for cheat sheets. Most dslr's come with abbreviated instructions.

 

Most of the "cheat sheets" are generic, a few have specific information (such as hyperfocal distance) that apply to particular models.

These might come in handy. I have a veritable library of photography textbooks that I have referred to over the years but nothing quite as portable.

 

Here is the web site:
http://www.photocheatsheets.com/

I bought one for each dslr and keep them in the appropriate bag for just in case moments where you are drawing a blank on some setting you may not have used recently.