Howdy Jamie,
As to the first question, host will be 1 of 3 values:
localhost. If the user you are adding will be connecting from the local machine (i.e. a web application running on the same machine as the database) then use localhost. That keeps the account from being abused by others.
% – this is the wildcard that means from ANY host. Be careful with this one.
The third value is the specific machine name you are connecting from (or if you are behind a firewall, the machine name of the firewall.) This will look something like dynamic-62-56-11-81.park-s46b.dslaccess.co.uk. This is the best option if you know you will be accessing it from the outside form from the same place each time. It's just a little more secure.
But the second question indicates that you have a problem that can't be fixed by SQLYog. The problem is you don't have permission to add users. You'll need to speak to your host about that.
Have a great day!
=C=
