South is a reasonable 15 so cannot bid 1NT so 1♥ the lower of 2 four card majors, givingpartner an easy bid of 1♠ .

South has to decide between 2 and 3♠ s.

3 aces are good, no good intermediates. Either bid is OK. 

In both cases North has a balanced  hand 5332, both Js are weak, so pass.

A lot of options for bidding.

Some East’s May open 2♠, not meeting the 5-9 HCP range but with an extra ♠. With the favourable vulnerability in position 1 some may bid 3♠.

when pre-emptying, the best position is 3, if partner has passed and the opponent on your right has passed and you have a weak hand that means opponent on your left has a load of points, so pre-empt if you have a long suit. Second best position for a pre-empt is in position 1. In position 2 you are at increas3 risk of pre-emoting your partner.

if East opens 2 or 3♠, west will raise to 4. North will with double and South will probably bid 5♥ , though 4♠ Should go off.

Standard 3♣ pre-empt by West.

North has a good 4 loser hand so needs very little from South for game. However the bidding is high. A double may clarify things. The danger for North bidding 3♠ is that it is easy for South to pass. Though the Singleton ♣ is important and support for ♠ s could make it attractive to bid 4.

After North doubles if East passes, South should bid 3♥ the lower of 2 4 card majors and kiss the better fit.

East opens 1♣, south overcalls 1♥ .

west can show support for the ♣ s. With 2HCPs many west’s will pass.

north with 10HCPs can bid 2♦ . South has probably denied 4♠ s as he bid 1♥ rather than doubling, so better to bid 2♦ s.

East and South pass.

west competes with 3♣ s and South can bid 3♦ s.

♥ 1♦ by South with an easy rebid of 2♣ .

West can show shape by overcalling 1♠ and then bidding the ♥ s.

North shows ♣ s.

As East can show ♠ support later, could bid 2♥ s.

South shows support with 3♣ s.

West knows of a 10 card ♥  fit so can easily bid 4♥ s based on the law of total tricks https://www.bridgebum.com/law_of_total_tricks.php

North should find a good sacrifice of 5♣ s.

Then west or East may find 5♥ s.

East’s hand shape is wrong for a 1NT, so open 1♥ .

South will overcall 1♠  and West will bid 2♥ .

North will pass.

East should pass. The Q doubleton and the Q♠ with a 1♠ overcall on left suggest caution.

South May double to compete though the shape is not great.

 West will probably pass, though 3♥ may be bid. Otherwise North will bid 3♦ and be overcalled by East with 3♥ S.

1♠  after 3 passes.

Then  East can bid 2♥ s with 8+ and 5s.

West can jump to 3♠ s with only 15 HCPs. Should be 16+ but West has 3 10s, unbalanced with a singleton and solidish ♠ s. If  west bids 2♠ s this will be passed out.

East opposite 16+ and 6♠ s can bid 4♠ s with a good source of tricks in ♥ s and 2♠ s.

Natural bidding until West on second bid can see a ♠ fit and around 30+ HCPs so can explore slam.

Normal Blackwood 4NT asks for Aces and East shows 2 Aces. East has less than 16HCPs (by bidding 2♥ s after a 1♠  opening bid) so a grand slam is unlikely (though it makes with the fineses available).

West opens 1♣  and East responds 1♦ .

West shows 17-18 HCPs by bidding 2NT.

East knows they have a minimum of 32HCPs and can bid 6NT. 

East has a standard weak 2♥ s

South with only a singleton cannot bid 2NT or double so bids 3♦ s.

North thinks 3NT is on with his 13 HCPS opposite someone who has overcalled, but he needs a ♥ stop. So bidding the opposition suit here is asking for a stop (opener has shown 6 so it cannot be a normal bid). South has great stops and bids 3NT.