1. See:
https://docs.woocommerce.com/document/woocommerce-localization/
2. By default, WooCommerce comes with a dropdown to allow sorting. If you can’t see this dropdown, it may be hidden by your theme. Have a look through theme options to see if there is a setting for it. Also, consider setting up a sidebar and using it for some of the WooCommerce widgets, such as Layered nav or price filter.
3. Products can be in multiple categories, so “sort by category” is problematical. Alternatively, you can set your shop page to “Show categories”, then the user can click through to the relevant product category page. You could also setup your menu with a menu item for each category, In Admin page > Appearance > Menus, look for the “Product Categories” section.
4. You can set a sale price (as well as the regular price) for any product. Its up to your theme how to show this. Some themes will show a “Sale!” bar across the corner of the product image for example.
5. Set your product to be a “variable product” type in the Product Data section. Describe your product in general terms. Then, in the Product Data > Attributes tab, set your size attributes. Lastly, in the Product Data > Variations tab, create a variation for each attribute. The user is presented with a dropdown to use to select the variation that they want.