Do i Just download each trial version of the creative suite and use the same serial number over and over again?
If you mean the individual, standalone software apps in the suite then no.
Each Creative Suite is a single, large self-contained download.
Adobe has now hidden the CS6 download links deep within their site so they're hard to find now that the CS6 versions are about to be superseded by the next versions (CC) next month.
You can download the CS6 Design Standard trial from http://prodesigntools.com/adobe-cs6-direct-download-links.html
Ensure that you follow the Very Important Instructions on that page first otherwise the download links will not work.
Once downloaded, launch the trial and enter your serial number once to activate the entire suite and every app within it.