One stage with 41 reward lines. bundle names the payout, cost 100 is the price per level, gold false means it is bought with the pass currency rather than gold directly. Rename a bundle to swap the payout, lower cost to make levels cheap. 
<battle_pass>
  <stage>
    <reward gold="false" bundle="Bundle_Battle_Pass_1_1" cost="100" />
    <reward gold="false" bundle="Bundle_Battle_Pass_1_2" cost="100" />
  </stage>
</battle_pass>
Activation dates live in default_platform_config.lua (battlePassStart/battlePassEndTable). Changing dates there resets player progress, so re-time first, then price rewards here.
Additional Notes: 

Dates in Lua reset progress; prices here do not.

Comments

4 + 2 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.