Hi Roy,
1st up I've a K2.... and assume the F2 is essentially the same..... Pete?
The unit you have replaces 2 original bits, ie the regulator (gold box) & the rectifier (black jobby under the fuse holder in the bottom pic)
The unit's loom plug you have (3 yellows / green / red ) connects to the existing loom plug that went to the original rectifier. (white terminal block, top pic / RHS)
The flying leads (black / white) go to the existing loom connectors (same colours) that fed the regulator. There will be a spare green left over (regulator earth) from the bike loom here... just tape it up & tuck it away.
The below (embarrassing) pic of my bike as I bought it showing those black & whites going to the bike loom, and my restored pic as a ref showing the original bits you're now replacing,
Along with Pete's wiring diagram hope this helps...
Simon