How a user connects to a public account.?

[it19862]

 

1. I want to chat with my users through a separate application (CRM). Number of users - 1-30 people The regularity of correspondence - 1 time in 0.5-1 month.  
2. I created a public account.  
3. Next, I try to invite the user to a public account, but I do not understand how to connect the user.  
4. I, as an administrator, sent an invitation to the user. The user has received an invitation.    
5. The user clicked the go button. The "window" opens. And nothing happens. In other words, viber does not connect the user to a public account.   Questions
6. Am I doing everything right?
7. How to connect a user (subscriber) to a “public account”?  
8. If "user_1", "user_2", "user _...", "user_n" are added to the "public account", then all users see each other as in a "community"?  
9. If in the "public account" user "user-administrator" sends the message "user_1" (or to other users) through the application (CRM, ERP), then this message can be seen by all other users or only by "administrative user" and "user_1" ?  
10. How to send / receive a message from the application (CRM, ERP) to users who are not connected to the "public account" knowing only their phone number? And can this be done?