B & A

BEFORE:
                                               QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------
 Aggregate  (cost=119.89..119.90 rows=1 width=8)
   ->  Gather Motion 6:1  (slice3; segments: 6)  (cost=119.80..119.88 rows=1 width=8)
         ->  Aggregate  (cost=119.80..119.81 rows=1 width=8)
               ->  Hash Left Join  (cost=33.02..117.30 rows=167 width=0)
                     Hash Cond: casts.actorid = actors.actorid
                     ->  Redistribute Motion 6:6  (slice2; segments: 6)  (cost=21.75..92.75 rows=167 width=4)
                           Hash Key: casts.actorid
                           ->  Hash Left Join  (cost=21.75..72.75 rows=167 width=4)
                                 Hash Cond: casts.movieid = movies.movieid
                                 ->  Redistribute Motion 6:6  (slice1; segments: 6)  (cost=0.00..36.00 rows=167 width=8)
                                       Hash Key: casts.movieid
                                       ->  Seq Scan on casts  (cost=0.00..16.00 rows=167 width=8)
                                 ->  Hash  (cost=13.00..13.00 rows=117 width=4)
                                       ->  Seq Scan on movies  (cost=0.00..13.00 rows=117 width=4)
                     ->  Hash  (cost=8.34..8.34 rows=39 width=4)
                           ->  Seq Scan on actors  (cost=0.00..8.34 rows=39 width=4)
 Optimizer status: legacy query optimizer
(17 rows)


AFTER:

                                                       QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------
(17 rows)
	  ----- Step1 -----

                                 ->  Hash  (cost=13.00..13.00 rows=117 width=4)

	  ----- Step2 -----

                                       ->  Seq Scan on casts  (cost=0.00..16.00 rows=167 width=8)
                                       Hash Key: casts.movieid
                                 ->  Redistribute Motion 6:6  (slice1; segments: 6)  (cost=0.00..36.00 rows=167 width=8)
                                 Hash Cond: casts.movieid = movies.movieid
                           ->  Hash Left Join  (cost=21.75..72.75 rows=167 width=4)
                           Hash Key: casts.actorid
                     ->  Redistribute Motion 6:6  (slice2; segments: 6)  (cost=21.75..92.75 rows=167 width=4)
                     Hash Cond: casts.actorid = actors.actorid
               ->  Hash Left Join  (cost=33.02..117.30 rows=167 width=0)
         ->  Aggregate  (cost=119.80..119.81 rows=1 width=8)
   ->  Gather Motion 6:1  (slice3; segments: 6)  (cost=119.80..119.88 rows=1 width=8)
 Aggregate  (cost=119.89..119.90 rows=1 width=8)
-------------------------------------------------------------------------------------------------------------------------
                                                       QUERY PLAN


So I tried to make it more understandable. I just need to understand the code more within this, I turned the code upside down as you can see because that's how it usually reads well.