In summary

1. Go to here https://go.xero.com/settings/users
2. invite chris@ttran.com.au, and teresa@ttran.com.au
3. and our permissions should look like this below. Notice it says 
   • ADVISER 
   • and MANAGE USERS

Full instructions

1. Go to SETTINGS
   
2. Go to USERS
   
3. select INVITE USERS
   
   
   
4. Insert the following information as shown in the arrows:
   

https://central.xero.com/s/article/Add-a-new-user-to-your-organisation

In summary