Dell PowerConnect 2848 MCLI Mode

Hi all, 

I have the switch put in production already. Now im trying to put some ip address and configurations. The problem is that when i connect it through the serial i have just the following prompt ">". Can i configure the SNMPv3 via MCLI or should i press the config/Managed mode button. Also becouse this is production switch, what will happen if i activeate the Managed mode ? Do i have to reboot the switch or the switch will reboot itself ?

Also is there a way to configure SNMPv3 via MCLI 

Thanks