I am sorry my answer didnt meet your expectations 
You didnt provide many of the necessary informations needed by the people on this forum to help you.
a rough guide can be found here How to ask a good question / Help Us Help You 
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So I have to take a guess here 
many people run there system on some kind of linux system or even use openhabian which is based on raspbian openHABian | openHAB
If this should be the case for you the next steps I will describe will maybe help you as a starting point. If you run openhab on another operating system I will unfotunately not be able to help you as I have no experience there. As a disclaimer I dont actually own your security system so this should only be considered a rough guideline for the first half of the setup. I can only help you setting up the mqtt part that you will need to connect to the alarm adapter.
So lets start.
As you have probably already read in the thread I linked there is no official binding for your project. But your lucky and somebody developed an adapter for it. This adapter GitHub - ParadoxAlarmInterface/pai: Paradox Magellan, Spectra and EVO, with MQTT, Signal, Pushbullet, Pushover and others is based on connecting to your alarm system and than offering a translator of sorts to a protocoll called mqtt MQTT - Wikipedia which there is a binding for in openhab MQTT - Bindings | openHAB. So in addition to the “adapter” and the mqtt binding you will also need to install a mqtt broker. The mqtt protocoll is based on the principle of having this broker and clients can subscribe and publish to topics on this broker. A great intro to this can be found here Introducing the MQTT Protocol – MQTT Essentials: Part 1 I can recommend reading the whole ten parts https://www.hivemq.com/tags/mqtt-essentials/.
So a popular choice would be to use mosquitto as your broker https://mosquitto.org/. If you are using openhabian you are in luck as you can find an option to install it in the openhabian config under additional components https://wiki.instar.com/Advanced_User/openHABian_on_Raspberry_Pi/Mosquitto_Setup/. Otherwise you could use a tutorial like this Installing MQTT Broker(Mosquitto) on Raspberry Pi : 4 Steps - Instructables. So once you have the broker and the mqtt binding installed you need to create a broker thing in paper ui connecting to your installed broker whith the credientals you entered when you installed it MQTT - Bindings | openHAB. Have a look here First time setup of MQTT [solved] - #17 by Archimedeus or here Migrating MQTT1 items to MQTT2.4 items if you are having trouble with this step.
Now you need to install your adapter to actually connect your alarm system. You will probably have to follow the manual instructions on there page here GitHub - ParadoxAlarmInterface/pai: Paradox Magellan, Spectra and EVO, with MQTT, Signal, Pushbullet, Pushover and others. Once installed you will have to follow the connection and usage instructions provided in their wiki Home · ParadoxAlarmInterface/pai Wiki · GitHub. Once you connected the interface to your broker the mqtt binding comes into play. You will have to create a generic mqtt thing MQTT Things and Channels - Bindings | openHAB that has channels that publish and subscribe to the topics specified here https://github.com/jpbarraca/pai/wiki#mqtt-interface.
From here on I cant really help you and you will have to comb through this thread Help build binding for Paradox Alarm Panel with IP150 - #327 by jpbarraca that I linked before.
If you have questions for connecting your system to the adapter best is to actually ask in that thread as those people own the system and probably wont find this thread here to help you. You can also communicate with the developer of the adapter here https://gitter.im/paradox-alarm-interface/community?source=orgpage.
I hope this helps you as a starting point on the journey and somewhat meets your wishes, im sorry I cant make it any easier or offer a plug and play option.
Best regards Johannes.