Event Issue

Hello all,
I notice some issues when create an event, i have a 2h show so after the top hour, i create an event to stop the AUTO mode, the next hour, after the top hour, another to start again the AUTO mode,
On the scope section, to stop the auto, i need only to tick automation + on-air?
And to start it again later on, just the assist + on-air?
I have tried several times to play with it, sometimes it works, other, it starts the auto mode but erase the show and the playlist goes blank…
I am sure that it is a pretty simple issue, but if someone could help, it would be great,
Many thanks