Here we are in a category called Number Shirts in my test store. You can see that there are 10 products listed on this screen. That's because by default the Category Display page will show products up to 10 at a time and if you have more than 10 products in your category, you can use these page controls to access them. Here we are on page 2 and you can see my products from 11 up to 20. The Miva Merchant software paginates your products 10 at a time by default, but that can be changed if you want. Click into your store admin, click on User Interface and look for the page called Category Display Page. Click into it, scroll down the screen until you see the pagination settings. Here you can see it's currently set to 10. You can change it to any number you might like. You can also bubble in the option “Do not Paginate Products” if you want the products on your category to be listed all on one page, regardless of how many products you have in that category. When you have your settings set the way you like, be sure to click “Update” to save your work.