Mom's Great American Potato salad

Mix together:

1 c. salad dressing
1 tsp. mustard
1/4 tsp. celery salt
1/2 tsp.salt
1/8 tsp. pepper
1/4 small onion, chopped very fine
1/2 c. celery slices
1/3 c. pickle relish (sweet)

Mix into:

4 c. cubed cooked potatoes (6-7 small potatoes)
4 hard boiled eggs cut up