How do you get third person in team fortress 2

you go to options and click on the keyboard tab, then you click on advanced then check both boxes in that window. then in game you must have sv cheats set to one(codes at bottom of answer) then in game you open the developers console with the [ `~ ] key and type in third person and there you go here are the codes

step one: enter sv_cheats 1
step 2: enter thirdperson
step three: enjoy