{{explanation}}
3s & 4s start on opposite sides

1-4
: Set+Link with "interchange":

: 1s & 2s also 3s & 4s, dance Set+Link but on bar 4 1s+4s pass on sides
  giving LH 2(4)1(3).
5-8
: 2s+4s also 1s+3s turn RH on sides, then 4s+1s 1/2 turn LH on sides, Men
  stay facing out end 2 1 (4) (3)
9-16
: 1s+4s dance Ladies' Chain
17-24
: RSh reels of 4 on the sides
25-28
: 2s+1s also 4s+3s circle 4H round to left
29-32
: All join hands on side and set, then 1s+4s dance 1/2 RH across. End 2 4
  (1) (3)