two people
从 centers on the idea of two people together, often implying one follows or accompanies the other. The core image is a pair of individuals in a close spatial or directional relationship.
从 is a compound ideograph of two 人 (person) side by side, representing one person following another. The modern form preserves this simple arrangement.
Two people 人 standing together, one behind the other, like a follower accompanying a leader. 从 is two people.
For ショウ, imagine two people following a show: show -> ショウ, and the pair walks together to see it.