If you are happy with the suggested eBay category, simply tick the box next to the most relevant suggested category.

You can also map multiple products at once by selecting the lefthand checkbox next to each product,  then clicking the 'Choose a category to list in' button. See the screenshot below.

Once you have finished mapping, go to the dashboard and click the 'Upload to Marketplace' button to list your products on the marketplace.

Relevant points to note:

Any newly imported products in eBayLINK  that are part of a Category to Category or Product to Product mapping rule will continue map to that eBay Category by default.   If you do not want new products to fall into your existing mapping rules then you can delete the mapping rule from both the Product and Categories page.

This applies when doing Product Mapping and Category Mapping.  If you select one of the eBayLINK  suggested Categories this will 'Create a mapping rule' which eBayLINK will continue to use when uploading products to eBay.