How to remove a snapshot? (2008 R2)

I just want to be sure that nothing has changed and that this is the correct process, as outlined in this other TechNet post here:

https://social.technet.microsoft.com/Forums/en-US/672c5a64-ff83-42c3-946d-c7beed341199/snapshot-on-hyperv-windows-2008-r2-server?forum=winserverhyperv

Right now I have a VM on a 2008 R2 host that I wasn't even aware was snapshotting, so it's been going for aabout a year and a half.  Consequently the .VHD file is I think around 250GB, whereas the AVHD file is around 600GB. 

As I understand it, I need to:

1. Turn off the VM 
2. In Hyper-V Manager highlight the VM in question
3. In the Snapshots pane it then shows two lines:  line 1 is the machine name and a date, May 2013.  Below that is a subline that says "Now". 
4. I right-click line 1 item, choose Delete Snapshot. 
5. Somehow the snapshot merges with the main file or something

Is that it?  Also there is an option for Delete Snapshot Subtree - just want to make sure I don't have to pick that? 

Thank you.