It's a lot easier than it looks.
This pattern is written assuming a color change every round. If the same color is used on multiple rounds sl st into the next convenient place to begin the next round.

dc cluster: Note on beginning: it works better to ch 2 rather than 3, then upon finishing sl st into the top st.
dc cluster: ch 2, start a 2nd dc but don't finish it and keep the last loop on the hook, repeat the last step; finally yarn-over and pull the thread through all the loops to make the cluster. The ch 1 that finishes it generally isn't included as part of the cluster.

hdc cluster: If it's starting a round ch 2, and if it's not starting a round begin an hdc then start a 2nd and third hdc with all loops on the hook; finally yarn-over and pull the thread through all 7 loops to make the cluster. The ch 1 that finishes it generally isn't included as part of the cluster.

Hook size: I; finished piece about 7.5“ with Rnd 6 or about 8.5” with Rnd 7.

ch 6, sl st attach (some like to use a “Magic Circle”)

Rnd 1: ch 4 (dc, ch 1), dc, ch 1 11 times; sl st into 3rd st of ch 4

Rnd 2: Attach new color, 3-dc cluster in top of ch 3, ch 2; dc cluster, ch 2 in each dc around; sl st into the top of the middle dc of the 1st cluster (12 clusters, 24 ch)

Rnd 3: Attach new color in ch 2 sp, ch 3, 6 dc (corner); *3 dc, ch 1 in ch 2 sp, 3 dc in next ch 2 sp; 7 dc (corner); repeat from * around, sl st into top of original ch 3. (52 dc, 4 ch 1 sp)

Rnd 4: In this round the dc cluster, ch 2, dc cluster, ch 2 make new corners.
Attach new color into top of ch 3 with an sc (1st dc of previous round) sc in the next 2 corner dcs, sl st in corner (4th) dc, sc in next 3 st; *skip st, hdc cluster, ch 2; (in ch 1 sp dc cluster, ch 2, dc cluster, ch 2); skip st, hdc cluster in center st of 3-dc, ch 2;sk st, sc in next 3 st, sl st, sc in next 3 st; repeat from * around to the last hdc cluster, sk st, sc, sl st to 1st sc to close (8 dc clusters, 8 hdc clusters, 24 scs, 4 sl st)

Rnd 5: In this round a different set of corners is created.
Attach new color in any corner's sl st, (ch 2 to start a dc cluster, finish cluster w/2 more st, ch 3, dc cluster, ch 1) in same st; sk st, hdc in next 2 st; *sc in next 9 st including ch 1 sps, hdc in next 2 st, ch 1, sk st, (dc cluster, ch 3, dc cluster, ch 1) in sl st; repeat from * finishing off with final 2 hdc, sk st, sl st to top of original cluster. (8 dc clusters, 16 hdc, 36 sc, 20 ch)

Rnd 6: Attach new color in ch 3 sp, (ch 2 to start a dc cluster, finish cluster w/2 more st, ch 3, dc cluster, ch 1); *dc cluster, ch 1 in ch sp; skip st then hdc, hdc, sc, sc, sl st, sl st, sc, sc, hdc, hdc, ch 1; dc cluster, ch 1 in ch sp; (dc cluster, ch 3, dc cluster, ch 1), repeat from * around; sl st into center of beginning cluster. (16 dc clusters, 16 hdc, 16 sc, 8 sl st, 20 ch)

Rnd 7: Attach new color in ch 3 sp, ch 2 to start a dc cluster, finish cluster w/2 more dc, ch 3, dc cluster, ch 1 (corner); *dc cluster, ch 1 in each of next 2 ch sp; sk 1 st, 3 dc in next st, sk 2 st, 3 dc in next st, sk 2, 3 dc, ch 1; dc cluster, ch 1 in each of 2 ch sp; (corner); repeat from *, sl st to top of original cluster. (24 dc clusters, 36 dc, an assortment of ch 1 sp)
Finish off.