You can read as many books about it as you like. But, for me the best way is to find a problem or reason to use the software then get on and solve that problem. The help in matlab and simulink is very good. Use it and the online information to find the functions you need and how to use them. But really, once you have a proble/need to use it, it is simple. Enjoy
The best way to learn MATLAB is YouTube, you can find many courses for beginners and when you become familiar with the MATLAB environment you can try to do some project in your field or create fun programs to solve your daily challenges, as a chemist, I created a "linear regression calculator" for myself.
You can try MATLAB onramp from the Mathworks website (https://www.mathworks.com/services/training.html). When you complete this training, you will be offered a certificate from mathworks.
I would say, start with https://www.mathworks.com/learn/tutorials/matlab-onramp.html ; and start programming your first coding project already. Best way to learn is "learning by doing". There are many tutorials, examples you can find on the MathWorks website. Look at Syntex documentation (i.e. https://www.mathworks.com/help/matlab/ref/for.html) and there are also examples connected to each syntex. Happy learning & best of luck.
Aside from using online resources available on The MathWorks, Inc. website (owner of MATLAB & Simulink software), as a beginner, you may find the following down-to-earth books very helpful:
-MATLAB Demystified by David McMahon, McGraw-Hill 2007
-A Concise Introduction to MATLAB by William J. Palm III, 1st Ed,. McGraw-Hill 2008
-Introduction to MATLAB 7 for Engineers by William J. Palm III, McGraw-Hill 2004.