Hi Tony,
I would make a guess/recommendation, but you could do it this way or another - the portable power supply will power the mount and Asiair directly. Then, Asiair (and the camera via the integrated USB hub) will power the rest of the equipment including the main camera, guide cam, dew heater, EFW and EAF.
I would recommend to also use the 12V DC outputs rather than the AC outputs to maximise on power efficiency. Asiair requires 12V DC. Pretty sure AM5 also runs on 12V DC.
Consumption wise this is hard to predict. From experience, it does fluctuate through out the night as guiding runs, cooling adapts to the changing ambient temperature, dew heaters kick in, mount dithers, autofocus runs etc.
In terms of capacity, go as big as you can as these are not easy/cheap to upgrade. I would recommend a minimum of 500Wh capacity which should easily last you a night with your equipment.
You can go the path of getting an AGM battery and a box. But if you know nothing about electricity I would recommend go for one of the ready made power stations.
Not knowing your budget, an example of a reputable brand and decent capacity is this one:
https://www.bluettipower.com.au/prod...-power-station. Has 2x 12V DC ports to power your mount and Asiair.
Another reputable brand is this one:
https://au.ecoflow.com/. I use one of their River power stations and I am pretty happy.
Hope above helps.