How do I print at actual size?

Can someone please walk me through how to actually print something at its true size? I've got this frame layout in a PDF, but I can't for the life of me get it to come out at the right scale—the border is supposed to be 10 mm, but whatever comes out of my printer looks totally off.

I'm guessing you're looking to get some full-bleed printing done here—you know, edge-to-edge.
That feature is usually called "borderless" printing, though I guess not every printer actually supports it.
Plus, every single model has its own specific limits on how close to the edge it can actually go.

My suggestion—maybe find a local print shop or somewhere that handles school projects—and just check if they have a printer capable of borderless printing.

P.S. if you could drop a link to the PDF, we could probably see exactly what we're dealing with.

If you’re using Adobe Acrobat Reader, just head over to the Print menu and take a look at the settings under "Page Sizing & Handling." You can mess around with the "Actual Size" option or try setting a custom scale to 100%. That should give you the exact dimensions intended by whoever coded the PDF.
For me, it usually defaults to about 93-94% scaling, but honestly, I don't really care, so I just leave it alone...

Check out ProPoster—it’s free, so just grab it. I used it once to tile images across multiple sheets, like printing a life-sized Spider-Man, but it should work fine for whatever you're trying to pull off here.

http://www.scribd.com/doc/229734522/Okvir here’s that document I was talking about, just download it so you can see how the layout is supposed to look 🙂

Looking at the document on my screen, I’d estimate there’s a 5 mm margin on all sides except the left, which looks to be about 20 mm—correct me if I'm wrong on that.

When I sent it straight to the printer without tweaking any settings, here’s what happened:
top, right, and bottom margins came out at 12 mm
left margin was 24 mm

The issue seems to be this:
View on imgur
By default, the document prints at 95% scale—which is what that red box is pointing out—because if I try to force it to 100%, this happens:
View on imgur
It basically assumes the printer can handle printing the frame right up to the edge of the paper, but not all printers can actually do that. It feels like a mismatch in the paper size or dimensions.

My question is: what exactly are you aiming for? If you need that frame to sit flush against the edge of the page, check my first post—you’ll probably need a printer with a borderless printing option. But, if you need the frame to stay at a specific distance from the edge, just send over the original Word doc used to make the PDF. I can fix it for you, assuming you tell me exactly how far from the edge you want it.

Hopefully that makes sense.

So I had this little epiphany where I converted a PDF over to a JPG and then just cropped the image down to the frame View on imgur and when you go to hit Print from Paint, you can jump into the Page Setup and manually tweak the margins like this View on imgur but for some reason, the bottom line just completely vanishes whenever I actually try to print it :/

Alright, I put the image you sent into a Word doc:
http://www75.zippyshare.com/v/38357940/file.html

On my office printer, I actually managed to get it to print—even though it threw an error saying I was outside the margins. On the physical paper, I ended up with about 5 mm margins on the top, bottom, and right, and 20 mm on the left.

Just to reiterate—it really comes down to the specific printer. There isn't some universal rule for how close to the edge a machine can print. For some printers, a 5 mm margin might be too small and you might not be able to get the layout you're looking for on every single device.

Alright, thanks for the help🙂