U.S. Terms

Materials:
5.00mm (U.S H/8) crochet hook or size needed to obtain gauge.
I used Rico Essentials Soft Merino Aran.
A note about this yarn Though it is classified as an aran yarn, it is much closer to a DK/LIGHTWEIGHT 3. If you are not using the suggested yarn, I would use DK/LIGHTWEIGHT 3 with a 5mm hook OR use Aran/Worsted weight yarn with a 4mm hook when you gauge swatch.
4-8 buttons (2cm/0.75in)

Gauge:
16 stitches/14rows= 10cmX10cm (4X4 inch) in hdc

Stitches and abbreviations used:
dc- double crochet
ch- chain stitch
hdc- half double crochet
In- Increase
PSM- place stitch marker
RSM- remove stitch marker
RS- right side
sc- single crochet
sl st- slip stitch
sp- space
st or sts- stitch or stitches
WS- wrong side