I bought these chairs for super cheap at an antique store and a flea market. With a little paint and a bit of work, I love how they look now! :)
First you need to take off all of the upholstery of the old chair. It is difficult-- and it does take a bit of time for this type of chair. You have to take out all of the staples and carefully take off the padding and save it for later. ***Remember to be careful when taking off the original upholstery. You need to save it to use as a pattern for the fabric you are going to use to recover the chair.
After taking off the fabric, use it as a pattern on the new fabric. (Sorry I don't have photos for this, I was a bit over eager when I was doing this project.) :) For the frame of the chair, since all of the upholstery is gone, you can paint the wood. I used extra black paint that my sister used to paint her furniture. You have to make sure that it is good enough paint that it will not chip.
Once your paint is dry and you have the fabric cut out, you need to stretch the fabric and use a staple gun or upholstery stapler to get the fabric in place before you put on the upholstery tacks. Once you have the fabric on, just put on the tacks to cover your staples!
For the second chair, it is super easy. Just lay your cushion on top of the fabric you want to use and wrap it like a present. I used tacks to keep everything in place. Then I put another piece of fabric on the bottom to hide the springs and the rough edges of the fabric.