Advice for first time on the dyno?

[superdutydixie]

Yep found a place that changes 125 for 3 pulls. Now I've never done this and looking for good advice to get the best numbers possible. Also I dont know what type of dyno it is yet.
Using h&s 300 on hot Tranny tune s1l tc lock in 5th at about 50mph, with mods in my sig. What numbers should I look for and how to go about running on a dyno. Thanks!!