The mod is made for multiplayer servers. If you wanted to play single player you could just load the game with the mod loaded and mess around in the editor. Just load into a server normally with dayz commander and then exit to the main menu. Hit Alt + E and you will be in the editor with epoch loaded. Or just create a shortcut to arma2oa.exe and edit the target to look like this:
"C:\Program Files (x86)\Bohemia Interactive\ArmA 2\arma2OA.exe" -nosplash -skipIntro -noPause -mod=@DayZ_Epoch
If you wanted it to save your gear and progress then you would need to install a database and server on your local machine. You could password it and set it to one slot so only you could join. Directions for that here:
https://community.bistudio.com/wiki/A...dicated_Server
Server Installation Instructions - DayZ Epoch