Race selection sytem

[Dominus15]

I need you to help me by telling me what system or trigger is used in this map that I will leave below, to be able to choose the race at the beginning of a game, what happens is that my world editor is somewhat old and cannot open certain maps, That's why I would like help if someone could put the triggers here in the hive so I can do it myself manually. Another thing I ask is that they be the ones on this map, because in the past I used a race selection system but it caused too much lag in my map, especially when I played using 8 players, and when destroying buildings it lagged too much. On the other hand, in this map, even if I used 8 players, it never lagged.

EDIT: I need to add that if you can also help me by showing me the triggers that you use to create the evasion aura of the naga witch, the truth is that I recently got an aura system in Jass but it is going too slow for me, and on this map I have not seen that problem , that's why I would also like to see what type of triggers it uses