Upon having the file, whether its 2D or 3D, you will want to have the inventor file saved to your drive
Step 1: Step 1 - Open Up a Drawing File/Remove the Border/ANSI
Open up a standard drawing file and remove the Border and the ANSI box so that the Drawing appears blank.
Step 2: Step 2 - Add Your Inventor File Onto the Drawing
Here, you will want to hit "Base" and have the desired inventor file selected. Make sure that the orientation is set to **Front** (Or whatever position you have your part facing)
Step 3: Step 3: Saving Your File As a .dxf
PART 1: You don't want to just save the file, You want to do "Save Copy As"
PART 2: Select the file type to be ".dxf"
PART 3: Go into options and choose "AutoCAD 2000/LT 2000 DXF"
PART 4: Here is what a default .dxf file should look like and is ready to be used
Step 4: Uploading the .dxf File to Instructables
In your instructable, you will want to hit the **PaperClip** icon (Or select upload files), and upload the .dxf file. It should be able to download and not show up as a bunch of texts.