[SOLVED] Questions about user management

This is my actual setup :
I had a joomla 4.1.6 website with about 600 users before I installed Moodle 4.1 (within the same domain).
The installation of Joomdle is working correctly,, I can access Moodle with any of the Joomla menus provided by Joomdle and all system checks are green.
(Please note that later on, I am planning to use Hikashop integration plugin to sell courses, but I have not installed it yet as I first want to configure users' management correctly)

Question 1: For security reason, I imagine that it is probably not a good idea to have all the Joomla users become Moodle users, but only the ones who actually buy a course or the ones I enroll manually. So what would be the best system for that ? Should I create a new group in Joomla ACL that would be dedicated to Joomdle students ?
Question 2: Then, could you please clarify for me how to use Joomdle user configuration ?
1- What are the difference between those 3 columns: Joomla Account, Moodle Account , Joomdle User ? The difference between Joomla and Moddle acounts is logical and easy to understand, but on the other hand, I don't understand what are Joomdle users ?
2- What does the option "Migrate users to Joomdle" do ?
3- What is the function for each of the 3 "Sync ...." action ?
Question 3: Is there anything else you think I should know about users setup and that I may have missed ?
In advance, thank you for those clarifications.

Oops... I just discovered this wiki article which I missed somehow and that seems to answer some of my questions :
www.joomdle.com/wiki/Migrating_existing_...Joomla_installations

In fact, it did answer all my questions.
Thank you !!

Great Just let me know if you have other questions.