There are two main ways to connect your monitors to your powered mixer. One is for powered monitors or those which you have an amplifier for. The other is for passive monitors you'd like to power with the amp in the mixer.
For powered monitors, you will utilise the 1/4" line level outputs on the tip of the mixer. There are two 1/4" outputs located on the top of the mixer and controlled via the Mon 1 and Mon 2 faders, along with their respective red send dials per channel.
The second scenario is to utilise the amplified outputs in the powered mixer. For this method, you will need to power the mixer off and toggle the AMP MODE switch into MON 1/ MONO. If you have more than one monitor, you will need to chain the speakers. Connect the first speaker to Output A. This will allow you to control the overall volume of the mains with the MONO fader and the Monitors via Monitor 1.