Notice the before picture. It has no detail, no muscular definition. Just kind of a mass of a human body.
Big guns did an incredible model of Arnold. I"m trying to get an after picture like that. He has muscular definition and everything.
Can you recommend me a tutorial that gets me on track with sculpting my before model and making it more muscular defined like the way big guns did his?
Pretty much any photos or anatomy books. If you can find a sculpting how-to book, maybe that will help. Few people make tuts on sculpting something like a person specifically, as many ways exist and all take a lot of time. Perhaps a search over at Gnomone for a dvd or a few other learning sites.
If you follow the zsphere link in my signature and view the threadgallery, you might find some of what you need to see how to start. However this is going to all depend on your skill level and ability to practice. 
I have found this a VERY good site for human anatomy info:
Warning= (some nudity)
I just got Zack PETROC’s video Digital Sculpting: Human Anatomy, It’s really really good.http://www.thegnomonworkshop.com/dvds/zpe01.html
I heard you can sculpt at like level 7 the highest res. Sculpt, add awesome drawings onto it. displacement maps or something… normal maps… all kind of maps… then drop your model to the lowest resolution but still use the maps you made so your low poly model looks high quality.
Is there a tutorial on this type of process?
The highest res is what your system can support up to the max polys the current Zbrush can handle.
Everything you are asking is already in the built in Zbrush HELP, and much of it is auto demoing scripts. Then grab the Zbruush Practical Guide that will walk you throough exactly what you are asking again. Then on the Zbrush site under Education, grab the videos. After that you will be fine.
Always start at lo res, then work up. Just like real sculpting or drawing or anything else.