Each entrance must have a MEZUZAH, Even if the room has more than one entrance, Each one needs a MEZUZAH.

The MEZUZAH should be placed where the top third of the doorframe begins.

The MEZUZAH should be on a little slant, the top towards the inside of the room.

Before placing the MEZUZAH we recite the blessing:

ברוך אתה ה' אלוקינו מלך העולם אשר קדשנו במצותיו וציונו לקבוע מזוזה