Generally speaking, take your time. Especially when working with the glue. This was the first upholstery I had ever worked on. Overall, I am very happy with the results. There are some areas I will need to revisit; but nothing major.
I assume you're asking about the center console armrest? The installation guide from Redline Goods indicated that a staple gun would work for installing the leather. I found my staple gun was not sufficiently strong to make the cut. Staples wouldn't make it through the plastic shell. As a result, I glued the leather in place for the center console as well.
What I found for all pieces (including the center console armrest) was that it worked well to test fit the material onto the piece to which it was getting attached. Then work around the edge and tape down the material as if it were glued. This way you could determine the best fit for the piece without committing to the glue.
I don't have any pictures of this step from the center console armrest but it was essentially the same.
When it came time to glue down the piece, pull up a bit of tape to expose the area to be glued, apply glue, let glue dry (as indicated on instructions), then pull leather taut and press down the glued areas to get a good bond. Just move around whatever piece you're working on.
When it came to corners, I tended to work in from both sides and then do the corners last. Sometimes pressing in place with a screwdriver (on the reverse side; not the side that will be visible) or other straight edge to get a nice corner.
