From the pattern:
This doily can be made very colorful - two sizes of thread can be used - bedspread weight thread in pink, size 20 in green, size 20 in white …doily measures 12” dia., use size hook which works well for you with the particular thread used.

A doily in 12 rounds features
shell in shell
chain in chain
a large central star with spokes of a long chain filled with hdc, dc and tr stitches.