The easiest is to connect it to a DMX dongle thats attached to your PC.
There is a lynx USB DMX dongle that works good, and an entec is commercially similar.
Those using smart strings here, typically run E1.31 (say from an etherdongle) into an active hub ... and the active hub
has a dmx out port on it. Then connect the express to that DMX out port.
If you use wireless, then the DMX out goes to the DLA Lynx Tx unit. THen each express has a ex/rx (receiver) on it ... that then gets the 512 wireless dmx channels.
Once you get your f16v2, you'll have a configurable port you can set to DMX and connect the express to that, then daisy chain the others after that. Each express has a built in spitter (two dmx outs) ... so you can always run both outputs to two different expresses ... and each of those can be daisy chained. At the end of each run, terminate that express with the jumper.
I'd be careful to make sure you alphapix is not still configured for LOR. Because it means the wiring the DMX out port is wrong, because LOR DMX is not true dmx, so I'd guess you have to set it to DMX (not LOR) in the alphapix to make sure the right wires are getting the dmx signal. Google LOR DMX convertor and you'll see images of the conversion that needs to occur. I suspect if this alphapix worked with your LOR units, then it will NOT work with an express till you change it to standard DMX.