Add new search parameter

Go to System tools → ConfigManager → Digizuite™ DAM Center → 4.0.0 → [Newest version]
Press Searches and then GetAssets
Press "Add"
Press "Choose metafield group"
Navigate to the metadata field you'd like to add (Usually beneath Asset → Shared → Asset Info or ... → Options)
Press "Done"
Press "Choose metadata field" and select the field you'd like to add.
Choose Freetext (Choosing anything else will make it a filter)
Change the ID to be "fX" (where X is a variable where you input the name of the search. It has to be unique.) (Usually you'd can just set an f in the back of the auto generated ID.)
Press "Create"
Press "Save" for the search (Not the entry)
Press the left arrow that says "Searches" - This will return you to the searches overview
Press the newly appeared gear icon in the far right of the GetAssets
Press Yes
A job should now start up
(Sometimes necessary) Recycle of DC through the IIS (Failing to do this, will result in your changes not being applied) - Sometimes you only need to refresh the page.
In the top right corner, do a search in the field named "Search in catalog" with something you know is unique for the metadata field you've chosen to add to the search.