use at a basic level not obvious

[RobP54]

just downloaded and installed, selected a number of files in explorer and initiated smartrename, I just want to rename them all to an arbitary value, why do I need to have file names in the "search" field to give any result, is there a wild card to enter that will select all files?

Its far from clear...

[LesFerch]

Presumably you wanted something like this:

New Name.txt
New Name (2).txt
New Name (3).txt

Explorer does that on its own. Just select the files and enter a new name. It will look like it's only going to change one file, but when you press Enter, all of the selected files will be renamed.

If you want to do that using SmartRename, check Use regular expressions, enter .* in the Search for field and the new name in the Replace field.

[ihorbond]

Agree, not intuitive at all. You would think that what you enter in the search box is used to match the files you want to rename but no, it's more like search and replace the matching part of the filename unless you use wildcard regex.