Okay, so it sounds like you'd be creating your company's first Inventor template, since everyone else is using AutoCAD. It also seems like there's no need for any network sharing yet, since you're the only user for now. I'm going to assume you've at least had some introductory training on the software - hopefully that's the case. Your situation sounds a lot like mine here at this company, except that I had prior Inventor experience from my previous job. There are a couple of others that use Inventor situationally here, everyone else is AutoCAD-based. I'm the only one that is majority Inventor and dabbles in AutoCAD.
Similar to AutoCAD, Inventor drawing objects are controlled by Styles. Styles are stored locally in the drawing, like AutoCAD, but can also be stored in a central collection called a Styles Library. For either method, you first start out by getting one drawing the way you want it, so there's no need to really get into those just yet.
The way I would suggest starting is to look at the File tab in your Inventor Application Options. This will tell you where your default templates folder is. In Inventor, there is nothing special about a "template drawing" - it is not a different file type like the dwg / dwt in AutoCAD. Instead, to be a template, it just has to be in the Templates folder. In that folder, you'll find at least two templates that shipped with Inventor (I'm still on 2010, so if they've added more samples I wouldn't know). Find the one that's closest to what you want (inch vs mm, etc), then make a copy of it and name it however you want. You'll make your template in the copy.
You will probably want to start with the most obvious thing, the title block. Open up your drawing, and look in the browser for the entry for the title block. Right click on it, and pick Edit Definition. You'll then be in a sketch where you can modify the sample title block to suit your needs. More than likely, you'll be making a block similar to the one you use in AutoCAD, so you can use it as a guide. I'd recommend poking around a little in the sample before changing anything, so you can get an idea of how it is constructed. This is also why I have you start from a copy - you'll always have the sample to refer back to later.
Start out with that, then post back with what trouble you run into and we'll work on sorting it out. I like helping people through this sort of thing because it often gives me new ideas for how to tweak my own setup, so I'll be glad to assist.
