Having trouble understanding multiple users on Free Zoho CRM account

Having trouble understanding multiple users on Free Zoho CRM account

I have a small organization with 2 users (myself and one external sales person).  I thought I'd try out Zoho CRM and so far I like what I see.  But I'm having a really hard time understanding the whole multiple user model.  I'm hoping someone here could just explain it a bit better than the Wiki/Online help (which really doesn't explain anything other than how the screens look).

What I have done is create one Zoho account for me.  I have put a few leads, accounts, potentials in there.  Now I want to give access to this data to my colleague who is creating his own Zoho account.  My goal is that he can login and see the same data I can see, so that we can share information, update activities, etc. for these leads.

I can create a user account for him, but when I put in a Zoho CRM ID, I'm completely the confused.  The form says two entirely different things:  It states that I have to enter a Zoho CRM ID.  Is this assuming he has already created a Zoho CRM account for himself, and therefore if that is the case what do I put here?  But separate to that field it states "Specify a valid Email ID for the user as invitation will be sent to that address".  So is that referring to an email address here?

I tried this both ways.  If I put in his Zoho CRM ID, it complains stating that the ID is already taken.  If I put in a new email address, he gets an invitation email, but it doesn't link to his existing Zoho CRM account.  Its just a registration form for a new account, and with that done it doesn't show up on my list of users as 'confirmed'.  So I'm back to square one again....

What am I doing wrong here?  This is a really nice looking CRM, but since creating and linking user accounts up is one of the very first things that a new or potential customer is going to do, its one quick way to shut the door on new business if this isn't simplified.

Myles