①"Good for you" (CONGRATULATIONS) It's good for you (GOOD FOR YOUR HEALTH)
and "good to you" (NO SUCH SENTENCE STRUCTURE) I'm good to you (YOU COULD CHANGE THE PRONOUN BUT THE MEANING WOULD BE THIS PERSON IS KIND TO YOU)
for + noun - I've got a message for Max.
for + gerund (verb+-ing) - Thank you for looking after my fish.
to + verb - I went to the pool to do some swimming.
This is only part of the "to", "for" rule.
②"I checked it out." (PAST SIMPLE) and "I've checked it out." (PRESENT PERFECT). To change from present to past, change "have" to "had", "I had checked it out." Other forms, "I have been checking it out."(PRESENT PERFECT CONTINUOUS) and, "I was checking it out" (PAST CONTINUOUS). This would mean you had/have done some research or simply just looked up some information about (it) some item or activity. You could have also gone to watch, look at or spectate - "I went and checked it out."
Hope this helps.