We're up to scene three of Act I so far, ad we aren't even finished with that: slow reading. Anyway, it's a whole set of characters and location. First we had the obscurely love-struck Orsino and his posse; then Viola, all "let the dead bury the dead." Now, Maria and Sir Toby and Sir Andrew--quaint and amusing, since we do not yet know how their plotting will turn sour. One could even mistake Sir Toby for Falstaff, although we will learn that he is less intelligent and imaginative than Falstaff, but meaner and more capable of wresting out small victories.
Sir Andrew strikes me as one of the more distinctive characters in Shakespeare--decent-looking, well-intentioned and prosperous but almost childlike in his gullibility. I've heard it said that he is a riff of on Mr. Justice Silence from Henry IV Part II: I guess I can see the basis of the insight but it is still too much of a stretch for me. He's something to watch and think about; still I can't quite figure how to take him, or how Shakespeare might want us to take hm.