Hello,

It's very good that you want to continue your studies again after a gap. If you have passed your 10th in the year 2020, then after two years you can take admission in any school for pursuing your senior secondary, there's no need to write private exam. You can join any regular school to complete your studies, as the vibrant atmosphere and the exposure, experience you will get in school is unmatched and you will not get this anywhere else. So I'll advise you to take admission in regular school and take the advantage of studying In a school.

But it's totally fine if you want to write private exam. You can contact schools for this who allow students to write private exams without attending the school.

To understand the concepts you can rely on any good YouTube channel and rely on ncerts to understand basics of the topics.

All the best!