Well, no "orderID" anywhere, so not sure what columns/fields you've always been referring to.
Seems in whatever "original" software has created and is working with these tables, it doesn't look as if you could even (list-)join them in Fabrik, because your tables seem to "originally" be joined via the "orderno" columns in both tables. Neither of them is a PK, but Fabrik needs one leg of a join to be a PK, as said before and per Wiki.
Even if it were the case and a Fabrik list join would work well (because you worked your way around it as described previously), now it's also clear that the "copy list" plugin would be unable to do the job, because it'd be unable to generate the "orderno" in either table.
The PHP list plugin could do so with the right code, but we don't know how the "orderno" is generated in the "original" software, so at this point it'd be a guessing game to replicate this in Fabrik... you say it's "+1", but it could be right or completely wrong, and if wrong, the original software might fail.
So, if you must work with these tables in both the "original" software and Fabrik, you'll have more work to do... add a FK in table B to make the list join work in Fabrik, finding out what sets "orderno", then writing several lines of code in the Fabrik PHP list plugin to generate a proper "orderno" and inserting proper row copies into the DB tables.