For Mounting Image File–
DISM.exe /Mount-Wim /wimfile:”C:\DeploymentShare\Operating
Systems\WIN7ENT\WIN7ENT.wim” /index:1 /MountDir:C:\Mount

*Note- In “” your .wim file path. Also its one continues command.

For Adding Drivers–
DISM.exe /Image:C:\Mount /Add-Driver /Driver:C:\Users\Administrator\Desktop\LAN_Broadcom_14.4.2.2_W7x64 /Recurse

*Note- The Above is one continues command.

For Commitiing changes–
DISM.exe /Commit-Wim /MountDir:C:\Mount

For Dismounting WIM File–
DISM.exe /Unmount-Wim /MountDir:C:\Mount /Discard