If you're lucky, the printer uses an icon like this one to show paper orientation:
The A ( or horizontal lines) show that the paper is printed-side up, and the folded corner shows the paper orientation.
Most copiers have these icons on the infeed for originals, my printer also has them in the paper bins.
For printing more pages on one sheet of paper, have a look at the printer dialog. On my HP printer, it indicates the orientation when you switch on the 'more pages on one sheet' option:
The folded corner matches the other paper orientation icons.
The dialog also allows me to select on which edge I want to flip the pages. Generally, if your printer is capable of two-sided printing, the printer dialog contains all the settings you need.
If your printer can only print on one side of the paper, it becomes more complex: you have to print one side, then insert the stack into the infeed again in the correct orientation to print the other side. And you have to set the printer to print the correct pages (1-2, 5-6, etc) which is time-consuming.