Simply install that block and choose Expanding Search as custom template. Thats it. If you want to add a search block without result, then choose Expanding Search Without Result as custom template.

Limitations:

Copying the block and use it in same page multiple times will not work. But you can copy one block and use it in other pages.

Also It is using few js files which might conflict with some other add-on or themes js. Though the possibility is very less. If you see any issues caused by this add-on, don't use it.