In Design; Trying to understand

I am new to In Design, just as I am to Illustrator and Photoshop, even though I know more on Photoshop, but only on the main information and main tools.
I have used Photoshop in the past 2 years of college and have learnt the basics, however, I have found that Illustrator and In Design have some of the same tools, which makes it easier for me to work with.
I have used In Design only once in the second year of college when I had to create a book on Colour. I found it hard at first, but eventually I got used to the tool. Practice makes Perfect.
I have managed to print off information on the tools, what they do, and on guides, inserting text, and colour etc.