Upgrading from Exchange 2007 to Exchange 2013

Hi There,

I have two exchange serveres 2007 SP3 and they are ruining on Server 2008 Ent and 2008 R2 Ent.

I setup a server 2012 R2 and installed an exchange 2013 on it and a friend of mine helped me on setting up the new exchange server and migrating the mailboxes.

Now all the mail boxes are transferred to the 2013,  and based on his recommendation I am in the stage of uninstalling exchange 2007 from my old servers.

I am reading about the process but based on the link below I have to do more things before uninstalling

http://www.exchangedictionary.com/articles/clean-uninstallation-of-exchange-2010-mailbox-server-guide

the instruction is for exchange 2010 and some shell commands are not working on shell 2007

I also found the link below:

http://blogs.technet.com/b/meamcs/archive/2013/07/25/part-1-step-by-step-exchange-2007-to-2013-migration.aspx

and I think I am at the stage 8 or 9, but I am not sure and also I do not know what to do if I am at the stage 8

Would you please advise me what shall I do to finish up the project or give me a link for it.

I have searched a lot but I was not able to find a straight forward instruction.

Thank you in Advance