Here are the possible solutions for it might follow one two three clue
Answer
Clue
Relevancy
hike
Clue
It might follow "one, two, three"
Definition
to go walking
dag
Clue
Former UN leader Hammarskjöld [Note: The circled letters comprise a three-word instruction that, when applied to one square in the completed grid, reveals a group who might follow a code of silence]
Definition
to remove clotted tufts of wool from a sheep
atatime
Clue
Orderly phrase that can follow one, two or three
anda
Clue
Either blank in a jazzperson's "One ___ two ___ one two three four"