really puzzled by how to insert my SD card into the camera, is a CF adapter required? or am I missing something? Thanks in advance.
Up until about 10 years ago DSLRs used CF cards, then they started introducing SD slots, some have both. CF cards were faster and more durable and the professional choice. They make them, bu I am not sure if I would monkey with SD to CF adapter and any issues that may arise there or with SD compatibility. If you own DSLRs you may want to just invest in one or two mid range CF cards, they are comparably prices to SD card and given your shooting a 5d2 you don't need anything too fancy.
The camera-front side slot is for a CF card, and the camera-back side slot is for an SD card. Face the CF card's label side toward you and insert the end with the small holes into the camera. If the card is inserted in the wrong way, it may damage the camera. With the SD card's label facing you, push in the card until it clicks in place.
Samy, the subject of the post was a 5dm2, these were well before Canon started allowing SD cards. There is a reason the poster could not find a slot next to the CF card.