newbee to LS SWAPS in need of some guidance 4l80 not shifting.

ok guys im jess new to this site and new to LS SWAPS . I have a 51 merc that i installed a 6.0 with cable throttle, trans is a 4l80, the computer is BLUE/RED connector. computer come off another ls that had a 700r hooked up to it.
so i got my car running and driving, however its seems to be stuck in 2nd gear i believe limp mode? someone told me the computer needs to be programmed for the 4l80?
if so i would like to see if anyone can guide me through the process. i did just buy a OBDlink LX not even sure if thats what i need to do the job. once agian i am new at this but would like to learn . thanks for any help.

Look on forum how to segment swap, pretty easy, just have to find a file in repository with same os as ur pcm. Was easier than i thought when i put an 01 4l80e in my 09 silverado. Worth spending the time to bluecat tune it also, should be able to search the forum and find instructables on both.