Not entirely sure I understand your question, but here's how the searching works:
If the search field is blank, the system returns all entries.
If you just want to see either "for sale" or "wanted" you can use the filter called "Listing" to filter for just those entries. Pick the type you want from the list, and hit the search button.
You can also filter by "Model" (Bugeye, Sprite, etc) and by "Owner" which is the person who made the entry.
Once you have a list of search results, you can resort the list by clicking on column headers you want to sort by. Click again to reverse the sort order.
Does this explain how it works well enough?