The pattern explains where in the right front band the buttonholes should be made using the cable needle - the first one after 7 rows, and the rest after 30 rows. When all the buttonholes are complete you will know how many there are - and the number of buttons needed will then be known.

Measurements
To fit chest
71 76 81 86 92 97 cms
(28 30 32 34 36 38 ins)
Length from shoulder
57 61.5 67.5 68.5 70 71 cms
(22½ 24½ 26½ 27 27½ 28 ins)
Sleeve seam
40.5 43 45 46 46 46 cms
(16 17 17½ 18 18 18 ins)

Each pamphlet has a different set of recommended yarns. The following are from the Peter Gregory version.

Materials
Peregrine 100% Courtelle Double Knitting
6 6 7 7 7 8 100 gram balls
Gosling D.K.
11 12 13 13 14 14 50 gram balls
Snow Goose D.K.
15 17 18 18 19 19 50 gram balls
Cable needle
Stitch holders.