This is a 180-card micro cube that only uses cards available for free within starter decks of MtG Arena (2022 card list). It is meant to be drafted on a website such as https://mtgadraft.herokuapp.com/ using a Winston or Grid draft and then brought over to Arena where you can perform some specific adjustments, outlined below.
Due to the poor mana base fixing options available and limited card pool, here are some things I suggest looking into:
You will notice there are no non-basic lands or colorless cards. This is because Starter decks don't typically have enough to justify slots. For this reason, it will be incredibly difficult to have a solid mana base to cast on curve. I suggest allowing everyone to add as many of the following non-basic land cards as needed to their decks: