I use globals.
Player_One_Active = 0 or 1
Player_Two_Active = 0 or 1
Then based on the above yes player is active I make player_X active
Active_Player = (1,2) numbers being player number
This is a double check type system.
Using a lot checks
System - Active_Player = 1
condition Player_One_Active = 1
Do this and that and that and this
Create function called end of turn or something and
turn Player_X_Active = 0
And swop Active_Player = 2 etc
and run function at end of players turn whatever that may be
System - Compare Variable is your friend in turn based lol
Edit: There are 3 tutorials online somewhere
already using turn based. Will try and dig up links