Adding pages and columns is easy,
Just right click on the folder/module where you want to add the page, and click on add page. Then choose page as per your choice(eg. Blank page, login page, etc)
For columns, you can use layout grid, present in the toolbox tab.
Hope it helps!
Thanks Rishabh for helping me in this issue.
You can add pages on clicking on by the right button on Myfirstmodule and choose the page you want as blank or list or any type.
For columns after you add the page you can add from the right side data grid or you will have multiple choices.