The tax app is found in the admin tools by clicking on the wrench icon in the upper right corner of the admin dashboard and then scrolling down to the Tax app and clicking on the purple TAX button in the right column.The Tax tab of the dashboard shows the existing tax options applicable at checkout based on a ship to address.

You will need to check with your taxing authority on what taxes you need to collect but if needed, you can set up different tax rates based on category of goods through the Tax Type tab on the tax dashboard. Once the tax type categories are set up, you can select which tax type each of your products belongs to on the Product Info tab of each product.

If you need to collect different taxes based on a ship to location, that is done through the Tax Add tab of the Tax dashboard.

On checkout the system will sort through existing locations to find all entries that apply to that order and apply the tax that has the most matching detail.  For example, if your tax table had two entries, a flat tax of 6% for country code USA with no specified states, and a flat tax of 10% for the country code USA and a state of New York; if the order was going to New York it would be charged 10% while all other ship to locations would be charged 6%.