Use 'pretty much' to make a statement less absolute and sound more approachable. The directions are pretty much correct, you just missed the last turn.
Pro Tip 2/3
Informal Conversation
'Pretty much' is casual and common in everyday speech but less appropriate in formal writing. We're pretty much ready to go out tonight.
Pro Tip 3/3
Understated Agreement
When agreeing with someone mostly but not entirely, use 'pretty much' to indicate minor exceptions. I pretty much agree with your point, although there are some nuances.