The instantsearch box install is very simple and involves the Mozilla „TinREAD Toolbar” add-on installing.
Click here for download / extension install.
The browser will show typical message for when installing a new extension:
Then restart your browser and will be asked for the TinREAD extension activation:
Starting from now on the TinREAD extension is active and should be used for direct acces to Union Catalog.
Enjoy using it!