Since the monotron only has one output that's what you have to use. Connect that to the microkorg Audio In 1/4 and set the switch to Line. You will need a 1/8 inch to 1/4 inch cable. Connect the microkorg outputs to your monitors.
And perhaps you should show a little patience in the future.
Indeed, you are more likely to get a timely if you were to post in one of the forum boards for your product(s), where you are more likely to get responses from people familiar with your products who've perhaps wanted to try the same things.
Then again, with audio inputs and outputs, you can't really go wrong.. you connect output to input. Set up the devices which are receiving to do something with the input, etc.
Also, Axxim, this is a 'Thread' (a 'string' of related messages under the same subject title). The different sections of the forum are called 'boards'.
Current Gear: Kronos 61, RADIAS-R, Volca Bass, ESX-1, microKorg, MS2000B, R3, Kaossilator Pro +, MiniKP, AX3000B, nanoKontrol, nanoPad MK II,
Other Mfgrs: Moog Sub37, Roland Boutique JX03, Novation MiniNova, Akai APC40, MOTU MIDI TimePiece 2, ART Pro VLA, Focusrite Saffire Pro 40.
Past Gear: Korg Karma, TR61, Poly800, EA-1, ER-1, ES-1, Kawai K1, Novation ReMote37SL, Boss GT-6B
Software: NI Komplete 10 Ultimate, Arturia V Collection, Ableton Live 9. Apple OSX El Capitan on 15" MacBook Pro