Then

If an ability says "do X then do Y", X is considered a cost and must be paid before you can perform Y. This is also applicable to abilities that say "you must do X to do Y".

Example

The The fallback content to display on prerendering skill line's Volley ability is "Deal a total of 4 damage, distributed as you choose among enemies adjacent to you. Then, place yourself in an unoccupied hex 2-4 hexes away from your current hex."

You must be able to deal damage to enemies adjacent to you, to be able to perform "place yourself in an unoccupied hex 2-4 hexes away". The damage is the cost to perform the movement.