East is fairly flat with only 11HCPs so will pass.

South has a choice between 1NT (my preference and 1♣ ).

Over 1♣   West will either overcall or double.

Over the double by West East will bid 2♠  that West will invite with 3♠  and East with a maximum pass will bid 4♠ .

Over a 1♥ overcall East will bid 2♣ the unassuming cue bid (if you play it - if not well worth having a look at Andrew Robson on the unassuming cue bid, with this 3 of the major would be preemptive) or 3♥ if not. West then has to decide between pass or kick it into game. West has a good quality overcall with the AQ and AJ and QXX sitting over Souths HCP are probably better and you know where nearly all the outstanding HCPs are, game is likely.

If South opens 1NT this is more pre-emptive and make it more difficult to bid.

With a natural 2♥ overcall (the suit is weak) East will invite with 3♥ and West will raise to 4♥ .

Those playing Landy will have more options (or other systems showing both majors) will bid 2♣ , East will bid 2♠ and West will invite with 3♠ and East will invite to 4♠ .