Preparing to install the doors I like to have the door set back just a little I think it gives it a better look. Put the door into the opening where you want it without the trim piece that we left loose on the hinge side of the door. Take a small pin & poke a hole using the missing trim piece as a reference point to find the middle & poke a hole into the floor do the same at the top of the door where it would go into the top piece of the door frame.
These spots are where the pins will go they will be used as hinges for the door to pivot on.
Cut the ends of the pins off because they are too long only using the top piece of the pin with the head on it. Take the door out of the opening & take a pin using your flat nose pliers & push it deeper into the bottom hole & the top hole with them sticking half way out. You want the head with a little bit of the shaft of the pin still sticking up.