You have no friends in DayZ. Everyone will shoot you, unless you group up with people. Crouch down (X) and walk slowly when near zombies.
Take note of where you spawn (It says it in the bottom right of the screen) and use this map to mobilize yourself to get gear: http://dayzdb.com/map#3.065.126
First thing you'll need to do is to get a drink (coke/pepsi), food (pasta, beans, etc..) and at least a handgun. Louder the gun, the more zombies you will pull. You'll also alert players in the area that you are around and might get shot. Best thing to do is to get used to the fact that you will die often, and try get to know the whole south of the map, including Cherno and Elektro (The two main cities in the south). Apartments in Cherno are good for getting gear, and the Fire Stations in Elektro are good.
This game is very difficult to play as an individual, so try find friends to join up with