Hello MPM, if you are already doing the Little Reader free trial now, all you need to do is visit your account page to download the trial Chinese content file and import it into LR.
Just click on "Account" at the top of the page, then go to "My Purchases > Little Reader > Content & License Keys" and you'll see a "Free Trial Content" section at the bottom of that page.
Again, it's important that you have installed the Little Reader software (whether it's the trial or the licensed version) because you need it to open and use the sample lesson files.