Importing someone else sequence effects into your layout and sequences is relatively easy, but there are a few tips that will help. There's no need to match your physical controllers or props to theirs.
Download, and unzip if required, the other persons sequence into a separate folder (eg: one called Imported)
Open xLights, go to the Setup tab and change the Show Directory to the folder where your imported sequence is (where their rgbeffects file is)
Open their sequence and then do a Render All
Now the easiest way to import (IMHO)(especially if you have multiple monitors) is to open a second instance of xLights, go to your own show directory and then create a new sequence.
Then got to Import/Import Effects and match their props to your props, also import all their timings.
This is where having the two instances of xLights open helps, as you can look at their layout and yours to help match props.
I usually save the mapping, really helps if you map other sequences from the same person/vendor (eg:
http://sequencearmory.com/ free ones)
There's a few other tips and tricks and one of the Aussie sequence vendors has a nice FAQ which includes the link to Keith's how to video -
https://rgbsequences.net/faq/