'01 Silverado sluggish starting

[C-Notes]

I have a '01 Silverado 2500 and when I go to start it, it is sluggish and doesn't turn over right away. It takes a couple of key turns before it'll fire up. I had the battery tested and he said it was fine, so I'm assuming it is the starter.

Question: I've replaced the starter on my '70 C-10 a bunch of times but never on a truck this new. Is there certain things I should watch out for or specific tools that I'm gonna need to do this?? Is it pretty much the same process?? Thanks in advance for any advise.