hello noel, you have to turn off the default navigation with arrows or swipe (basing on the output format you are using) and use a Run JavaScript action in a button to let the user change page, with simple code like this:

const pagesCount = Object.keys(pubcoder.pages).length;
const randomDestPage = Math.round(Math.random() * (pagesCount-1)) + 1;
pubcoder.goToPage(randomDestPage);

As another user just asked on support, a quickly wrote a variation on this where you can just pick a random page from a preset of pages (not from the entire book):

const pagesToPickFrom = [2, 17, 20, 27, 35, 43, 46];
const index = Math.round(Math.random() * (pagesToPickFrom.length-1));
pubcoder.goToPage(pagesToPickFrom[index]);

You can extract the randomly chosen item from the array, save the result in the localstorage and get the array from localstorage if there's one. Of course it gets a bit more complicated, but should be something like that (not tested):

// First, check if there's already an array of choices stored in local storage
var savedChoices = JSON.parse(localStorage.getItem('choices'));
if (!savedChoices) {
    // If there's no saved array or it's empty, use the provided choices
    savedChoices = choices;
} else if (savedChoices.length === 0) {
    console.warn("every choice has already been made!");
} else {
    // First run, setup the array of choices
    savedChoices = [2, 17, 20, 27, 35, 43, 46];
}

// Now, choose a random value from the saved choices array
const randomIndex = Math.random(Math.random() * (savedChoices.length-1));
const chosenValue = savedChoices[randomIndex];

// Remove the chosen value from the saved choices array
savedChoices.splice(randomIndex, 1);

// Save the updated array back to local storage
localStorage.setItem('choices', JSON.stringify(savedChoices));

// go to page!
pubcoder.goToPage(chosenValue);