Below are a few helpful resources recommended by Mohamed Ismail to get an introduction to using Grasshopper.
Digital Toolbox
Link: http://digitaltoolbox.info/grasshopper-basic/
Digital Toolbox provides a great introduction to Grasshopper for those who have never used it before and want to quickly learn the basics. These tutorials are short (2-10 minute) video overviews of Grasshopper's key functions.
LinkedIn Learning
Link: https://www.linkedin.com/learning/learning-grasshopper
LinkedIn Learning has a 4-hour, beginner-friendly video tutorial for Grasshopper that goes more in-depth than the Digital Toolbox tutorial. A LinkedIn Learning account is required to access this tutorial, but there is a 1-month free trial.
The Grasshopper Primer
Link: http://grasshopperprimer.com/en/index.html?index.html
The Grasshopper Primer goes more in-depth than the other two tutorials and unlike the others, is text- and image-based, rather than video. This tutorial includes more of Grasshopper's higher-level functionalities.