How do I call functions in Move?

Question

I currently have this function

public entry fun create_game(
        account: &signer,
        prize_pool_amount: u64,
        player_one_address: address,
        player_two_address: address
    ) acquires State {
        // TODO: Call `check_is_state_exists` function

        // TODO: Call `check_if_signer_is_contract_deployer` function

        // TODO: Call `check_if_signer_has_enough_apt_coins` function

        // TODO: Call `get_next_game_id` function

        // TODO: Create a new instance of Game

        // TODO: Add the game to the State's games SimpleMap instance

        // TODO: Transfer `prize_pool_amount` amount of APT from `account` to the resource account

        // TODO: Emit `CreateGameEvent` event
    }

And I need to call a handful of other functions. I was wondering how I do so?

I tried searching through the documentation but couldnt find any answers