Also there is an arrow on the case near the rear LNB. This should be pointing down.
When I installed mine, I was replacing my old feedhorn and
C-band LNB.
What I did was left my big dish pointing at a C/Ku satellite before removing the old feedhorn/LNB - made sure I was receiving a signal.
Then installed the new C/Ku LNBF. Then connected to coax to the Ku LNB and moved the LNBF closer to the dish and further away from the dish and watched the quality signal meter on my TV. Left it where it got the best signal.
Then turned it slightly clockwise and counter-clockwise (skew) to get the best signal. Then tightened the bolts.