Critical skills work visa and family re-unificatio (Dublin)

Good evening all

I am working in Ireland on a critical skills work permit and one of the benefits of this permit apparently is the fact that my immediate family are able to join me here in Ireland at any given time from my understanding.
Are there anybody outthere that are also working on the same type and visa whose family have joined them in Ireland and living here with them?
If so what process did you follow to get them legally residing in Ireland? Eg, did they first came over on another type of visa and then register them as well at the GNIB? If so what did this entail?
I am from South Africa and the plan is for my wife and kids to join me here in Ireland permanently from Dec Protected content I just wanted to make sure we follow the correct process and have all the necessary documentation .
Any advice will be greatly appreciated.
Fyi: I did do research on the GNIB website but it is not very clear in what is exactly required or what process to follow.
Regards,
Jacques