Hi and welcome to the forums!
I am sure there is a quick and dirty solution to get what you have done out on a proper size, but since I am not of an imperial nature I can't help you with that.
I can however do my best to explain the long solution to get your drawing in working order.
1. At the bottom of your screen you have two tabs: Model and MAster. Highlight everything that you have on the Master-tab (ctrl+A) and Cut and Paste it to the Model-tab.
2. Scale (command SCALE) everything that is now on your Model-tab so that it's drawn at 1:1-scale. This is the most important thing in autoCAD, always draw at scale 1:1 in Model space. As to what factor you need to use to get it to scale, I can't help, I am a metrics only kind of gal.
2a. Right-click on your Master-tab and choose Page Setup Manager. Click Modify and select the printer you want to use and the paper size that you are after. Make sure that you have Plot Scale set to 1:1.
3. On the Master-tab, create a Viewport (command MVIEW). Double-click inside the viewport to activate it, if you do not see your drawing in the Viewport, double-click on your scroll-wheel to zoom everything.
4. Double-click outside your viewport do de-activate it.
5. Hightlight the viewport, bring up the Properties-palette (command PR) and assing a Scale to the Viewport. This is your plot scale.
This should get you started. Don't worry if it looks like just too much - almost everyone feels a bit overwhelmed until you get a hang of the use of scale in autoCAD.