How do I reset my SX215 to factory settings

Many duplex printers have an automatic setting for booklet print. If not, you have an option in the printer settings for long side or short side flip. If you are printing an A5 booklet (ie A4 folded) the setting should be landscape, two pages per sheet, flipped short side.

The widest paper to fit through is 8.5 inches. You can print up to 44" in length though.. from a Google search:
Automatic Document Feeder: 30 sheets. Paper Sizes: 3.5" x 5", 4" x 6", 5" x 7", 8" x 10", 8.5" x 11", 8.5" x 14", A4, B5, A5, A6, half letter, executive, user definable (3.5" - 44" in length) Maximum Paper Size: 8.5" x 44" Borderless Sizes: Photo: 4" x 6", 5" x 7", 8" x 10", 8.5" x 11", A4, 16:9 wide.

Have you checked the printer settings when you get the print screen?
Most likely it is set up for A5. That or the page layout of the document is set for A5.

You can get special overhead film for your Epson printer. It is coated for use in your printer, and has a backing sheet so the paper sensor can see that paper is loaded.

At the bottom of the printer you will find the paper cassette. Pull the handle and the cassette will slide out. Eventualy you will need to ajust the size of the paper.

solution clean the paper sensor and service the two solenoid that's the problem inside the printer

The paper you have inserted into the printer, and your page size settings have to match. You can't load A4 paper and tell it to print A5 size. This is why it is printing so small on the A4 paper. It assumes you need to trim it down to A5 size after printing.

Your printer ran out of black ink. You have to buy a new cartridge or refill the black ink. This will solve the problem.

no thats why it is not working the right way you have to use the semi gloss paper thats what it requiers

Usually if you see the page in the Publisher window is already landscape, it will go landscape in the Printpreview and also in the print out. I just try to imagine what is your problem.
If I am not mistaken, this is what you did:
You have two "small" pages (maybe A5??) and you want to print it in one page of A4. Of course the A4 should be landscape.
Publisher does not have the facility to set 2 pages A5 in one A4 like in Microsoft Word.
The easiest way is just create a new page with A4, then copy the 2 pages (or you called it flyers) and paste it in that A4 landscape page.
Publisher can do print 2 pages A5 in one sheet A4 but the arrangement is as booklet. You can see the choices in File --> Page Setup --> tab "Layout" --> scroll the Publication type.
I do print 2 pages A5 in one sheet with many variations using addition software named "Clickbook".
Let me know if I m wrong in interpret your problem.