To speed up your current process (importing one at a time)
You can import all at once if needed ..
Open RB (new blank file)
Open Windows Explorer (or File Explorer) window
Navigate to folder with desired wav files
Select all the wav files by holding the CTRL key and clicking each one
Click/Hold/Drag the set of files onto a blank empty track in RB ..

Wait a moment for RB to do the work (you'll see each track come in)

The first wav goes to whatever track you dropped on
The rest go onto the next available blank track (if memory serves correct)

I do not work here, but the benefits are still awesome
Make your sound your own!