Welcome to BricksSE! No question is silly (Maybe duplicitous), but never silly.
- Go to Bricklink.com
- Create an Account.
- Go to "Want" drop down menu.
- Click "Wanted List".
- Look for the blue box that says "+ Created Wanted List".
- Important: Create and give the new list a meaningful name other than
"default" or all future uploads will be merged into one list named "default" (very annoying).
- Go back to the "Want" drop down menu and click on "upload". You'll get the screeny below.
- Find your build's file location. Make sure your file is a compatible upload type.
- Click, Hold, Drag, and Drop your file onto the upload screen.
- Upload your pieces to the meaningful Wanted List name you've created.
The site fills in the magic of getting you connected to the people who'd like to sell you your parts.
Note the condition of each part after you upload can be new, used or any.
If you're buying Tiles, always buy them new. Scratched Tiles always look bad.
For any type of brick, always buy these colors new too: White, Yellow, Blue, Light gray. They tend to also make your final build look... worn if bought mixed or used.