Welcome, and thanks for posting in our Community forum! It sounds like you are on the right track here. I’m happy to help.
To include taxes in your sales price you will go into Settings > Taxes, as you mentioned. From there you will see the option to check a box that says 'All prices include tax.' It's under the Tax calculations section:
Keep in mind, if you want to use your customer's local tax rate, then check Include or exclude tax based on your customer's country. Including or excluding tax based on your customer's country is currently in beta, and might not be available for all stores. After you have set up your prices to include taxes, leave Charge tax on this product checked on your product pages so that the taxes are included in the displayed price. Customers will see the included amount of tax beside the total at the checkout. You can learn more on our help document: Include taxes in product prices.
Please let me know if that helps! In the meantime, I'd love to hear more about your business. Is this a new venture you've started recently?
Just checking in with you. Were you able to find that option in your tax settings? Otherwise, I would be more than happy to continue working on this together.