One station's instructions: who it is, which subcarriers it gets, and at what rate and power it must transmit.
Reading a capture
Five octets per station, and the frame carries as many as it needs. This is where an AP decides, per station and per transmission, how to divide the channel — the scheduling decision that used to belong to whoever won the contention.
Subfields
AID12 — The low twelve bits of the association identifier this instruction is for.
RU Allocation — Which resource unit — which block of subcarriers — this station must transmit on.