I'm trying to get a grasp of simple toy games, but I'm so clueless that I can't even model properly.
I'm reading first Brokos book and I want to model the situation below but... I'm not able to.

Taking my GTO+ sim here
1. Do I have set up the ranges correctly? When IP has A for example, OOP would only have K or Q?
2. How can I set OOP checking frequency to 100% to see different changes in equilibrium?

To better model real poker situations, we're going to play the same game again, but this time both players will have identical ranges. Each player antes $1 and is dealt a single card from a three-card deck consisting of one A, one K, and one Q, but this time either player could be dealt any card. The only information a player has about his opponent is that the card in his hand can’t be in his opponent's hand. In other words, if Opal has an A, then she knows that Ivan's range is {K,Q}, and if Ivan has a Q, he knows that Opal's range is {A,K}.

The objective of the game is simply to hold the higher card at showdown, with an A being the highest card and a Q the lowest. There are no community cards and no draws, just a single round of betting followed by a showdown.

We'll start by analyzing this game with only a half-street of betting. That is, the out-of-position player (Opal) is forced to check, while the in-position player (Ivan) may either bet $1 or check. There's no raising allowed, so if Ivan bets, Opal may only call or fold.