What can I do to join isro
In order to join ISRO you have to complete your M.Tech from IIST.
In order to be eligible you should have complete your B.Tech with minimum 60% percent for general category.
You need to complete your bachelor's degree in engineering first. You can appear for the entrance exam in your 12th class.
Currently, you are in class 10th so focus on your boards exam. Make your concepts strong for 11th and 12th class it will help you to clear the entrance exam.
All the Best!!

Your CGPA should be 7.5 in your graduation.