I have Acer apire desktop how to get CD dvd drive

are you asking how to add a dvd drive into your desktop computer ? if so we need model of desktop you have (look on label from acer)
are you asking how to add DVD drivers (what makes the dvd drive function? then we need to know model of desktop and what version of your operating system you are currently running (windows,? Linux? and version of the OS 7,8,10, x32., x64 etc. )