I have been a web designer for many years but have very limited experience in Joomla. I have been tasked with creating a master website that will control the template and some content for 4 slave sites.

I have purchased JMS as well as Multi Sites Content and Multi Sites Menu Item.

I have successfully installed all and they seem to be working.

I have read through the maunal and watched the first couple of tutorial videos but I am still pretty confused.

Can someone explain in laymans terms the method for creating a slave site from the master that I have running?

My impression was that I could control slave sites residing on the same dedicated server but with their own account (cPanel, FTP and so on), was I wrong?

Thanks in advance for your help.

The tutorial give you step by step procedure because the procedure is specific to each environment.

The reply that I will give you here is only applicable to Unix platform that accept the Symbolic Link.
In this case, you can create your first slave site in using the tutorial step 9 procedure.
This procedure consist in the creation of a slave site into a sub-directory with usage of Symbolic Links.
It avoids the configuration of the hosting provider http server.

When you want to create slave site with domain name or sub-domain, you have to configure the hosting server in aim to have a directory allocated for the domain.
Once you have this directory, you can check the path used by you hosting provider for this domein with the usage or the "hello world" procedure (see tutorial step 7).
Once you are sure of the path, you can create a new slave site using the same tutorial step 9 and only change the domain name and the deploy directory.

I suggest you to start doing that in the SAME cPanel account before trying repeat the operation with another cPanel account.
Once you will be able to create a slave site with a domain and have understood how to know the directory path assigned by your hosting provider and the usage of the deploy folder in JMS, you can retry with another cPanel account.

The problem that you may encounter with different cPanel account is relative to the permission to access the files and folders present into another account.
In this case, perhaps your hosting provider will not give you permissions to access the files and if this will be the case, you will eithe have to request give the permission (chmod 777) to the different account or a least to the same group of account.
Sorry but this part require Unix administration skill that is not necessary easy to setup if you have to do it yourself.

I also suggest that you review all the concept presented in the tutorial step 0.
It will show you the relationship between the domain and the directory path.
If you are using several cPanel account you will have to check that unix permission allows you accessing the files of another cPanel account.