To find the products you are interested in, click on a general category within the first box above. Clicking within the first box will then present you with the relevant subcategories in the next box along.
Click the relevant subcategory within the middle box to drill down to the last level (the right hand side box). Then, simply click on the relevant subcategory within this final box.
The Product Picker will then display a table of results for your "pick".