Congratulations on scoring well in your board exams. You are eligible to apply for an arts program at the University of Manitoba. However, your score should be no less than 60% in each course-
A third academic course
A fourth academic course
Yes, you're eligible to apply for an undergraduate program at the University of East London since the minimum requirement is 60% from CBSE board. However, you will also have to appear for the IELTS or TOEFL exam.
Do internships in your field of study
Do some certification courses. It will help you build your profile for the course you want to pursue.
Not related to CS, but doing volunteer work also helps create a strong profile.
You can also work on a research paper if that interests you.
For the problem that you have you first decide in which university you want to study and then explore their website i am sure you will find a way to get an admission in the university you want, there would be a segment or a web page for international student from there you might find contact details, contact number or an email through which you can contact them i am sure you will get the answer for your solution.