In KM links you can choose any word length - in MM links bet 4 and 8 letter words are allowed.
Yes just choose any words that you think might "go with" the links
KM scoring - 1 point for a correct match (answers are out on Mon from herculis puzzle in the telegraph) 3 points for 2 matches, 6 points for 3 matches, 10 pts for all 4 - no time bonuses here.
MM scoring - same , but bonus points if you guess the link in the first 2 mins (after 9am) or if you are the first to guess a link after 9am.
MM results are usually on the site at 7pm sun evening - but this week our setter is from Oz, so the answers might not appear till Mon morn.
In MM links, the winner of the month sets the links next month