When you are on map you can press a key that show all commander tags that are not hidden for you and you then get list and can select join this commander.
The commander can select hidden and there if he want only Guild member to see it or players on his friends list, can ofc select both.
Or he can select show, there he have automatically join or ask, automatically join then everyone that select to join him get in his squad, ask then commander get up symbol somewhere on the screen that someone want to join and then can open window were he see player x lvl x want to your squad and he can tick in Yes [ ] No [ ] and then ok.
That way if the commander don’t want up scaled to follow him he can block it.
Ps and commander can select show all other commanders my tag.