How to use Sanke mashtun?

[Golddiggie]

Id have to mash and transfer to a container, clean out keg and transfer back to keg. Is a sparge arm necessary? Can I just heat sparge water and slowly dump over grain bed?

Look up batch sparging... The only 'arm' typically involved is the one connected to your shoulder. Some dump/pour into the mash tun. Others use a fitting and use hose to run the sparge water.