Does "Print Preview" appear to be correct?
Do other documents print correctly?
Open your booklet and make all of the special characters (Returns, tabs, page breaks, etc.) visible.
Start searching through all the headers and footers as well. Look for some stray codes and settings: e.g., Page"x" of 'y"....
See if you can get the booklet to print correctly just one page per physical sheet.
Check the printer's configuration: paper size, doublesided printing settings etc..
The key is to identify what specifically is happening. May appear random but that is probably not the case.
Try printing the first two pages. Then the next two pages. Narrow down things down to where the problems begin.
Word has many, many configuration options. And the printer does as well. Getting it all under control will take some effort.
Take your time, be methodical, and and strive to identify exactly what is happening. Be sure to save your document as you go along,