As Jesper pointed out you don't need a FB, a FC will do fine. You need to create a send and receive DB where all the info in and out is stored and then a couple of networks to move data that you need.
There's not so much data so it would be easier to load and transfer what you need.
A little trick to speed things up is also to open one of the blocks as an instance DB (it doesn't need to be an IDB).
For example, you want to mive data from DB20 to DB11, neither are an instance DB associated with a FB.
OPN DB20 //Opens DB20 as normal
OPN DI11 //Opens Db11 as an instance DB, you now have two DB's open at the same time.
L DBD 2 // Load bytes 2,3,4 and 5 into accu
T DID 2 // Transfer into instance data from byte 2.
Of course if you did this within an FB you would have to read the altready open DI first and open it again once your finished transferring, best to do only in FC's.
L DINO // reads the current instance DB thats open.
saving that in a word and using it later recovers your proper DI, a crash is likely if you didn't.
i.e.
L DINO
T TEMP_WORD
Transfer code..............
............ End
OPN DI[TEMP_WORD]