Cakewalk Guitar Tracks 2 doesn't ship with documentation beyond the included quick start guide. Instead, the manual is reproduced in electronic form, and is available to you from the Help menu. You can conveniently search by keyword, which makes this electronic version easier to use than the printed version would be. I'd recommend you click the Getting Started button in the Quick Start menu that pops up when you launch Cakewalk (if you don't see it, choose Help | Quick Start). This will run through the basics of using Cakewalk to record MIDI and audio, as well as other topics. You can also access help topics by pressing the F1 key at any time.
In addition, we have posted many tips, tricks, and answers to common queries in the Support section of our website. There is also a new book called Cakewalk Power by Scott Garrigus. The book is available from Amazon and covers lessons applicable to all new Cakewalk software.