i bought some jigs recently and some crawfish plastics/trailers my question is how would i attach the crawfish to the jig

 Thread it on starting at the rear of the bait. Running it out the top about the length of the hook from the jig head to just past the first bend in the hook. If using a chunk or pig type bait run it through the bait from bottom to top with thick side down...

skillet

You can thread it on or just run the hook through the end of it somewhere which gives it more movement and lets it wiggle more and what-not.

You can thread it on or just run the hook through the end of it somewhere which gives it more movement and lets it wiggle more and what-not.

I agree. This is what I do with grubs when I want to trail them.