You will find the red + button in the upper right hand corner of the screen, wherever you are in GLIDR. From here, you can add Ideas as well as Posts, Discovery Tasks and Evidence. You can also click on any of the other + buttons on your Canvas, as shown below.
NOTE: Keep it brief! There is a 100 character limit. You can add more detail by opening the idea card.
Find out more about adding more detail to your Ideas here.