You inherit the spells at each indicated druid level in the Circle of the Beast Spells table as druid spells.
When you use your Wild Shape ability, you can chose a beast with a level equal to your druid level, instead of only half. Moreover, when you transform, you gain temporary hit points equal to your druid level.
When you take the Attack action while unarmed and transformed by your Wild Shape ability, you ignore resistance and immunity to bludgeoning, piercing, and slashing damage.
When you transform using your Wild Shape ability, you can increase your size by one, to a maximum of huge. If there isn't enough room for you when you transform your size, you attain the maximum possible size in the space available.
You can cast your druid spells while in Primal Form without providing somatic, verbal, or material components that don't have a cost or are consumed by the spell.