Welcome to the forum.
Go here
http://www.bossus.com/gear/productdetails.php?ProductId=1058&ParentId=248 and download the latest drivers for the BOSS and your operating system and install them.
The ME-24 is an audio interface as well as a stompbox.
Connect it via USB to your computer and in SONAR LE, select ASIO as the Driver Mode and the BOSS as your Recording and Playback device, or Recording and Playback Timing Master, depending on which version of SONAR LE you have.
With Roland/BOSS's ASIO drivers, you should be able to get latency down to ~ 10 ms or less.
Record everything through the BOSS, and plug your headphones and/or speakers into it to monitor what you're recording and playing back.
Good luck!