You can take admission in Computer Science and Engineering in three types of course i.e., Diploma, BTech and MTech.

Now Diploma in CSE is offered by different polytechnics and you have to qualify the polytechnic entrances in order to get admission in the course. Now as per your state, you have to search when the forms are out for the polytechnic entrances.

To know about the polytechnic entrances in India visit the link below:

https://engineering.careers360.com/articles/polytechnic

The basic education qualification for Diploma course is that you must have pass 10th or 12th.

Now the admission in BTech course is offered by engineering entrances conducted nationally or by state or by the institution itself. As you know JEE MAINS is going on and after the release of the results one can seek admission in NIT's and JEE MAINS accepting colleges. Now other state engineering entrances are going to be organized in the August. Thus based on your entrance examination the admission will be available as per the counselling.

Also after diploma you can admission in BTech by qualifying the later entry examination conducted by your state. For this case you will get direct admission in the second year of BTech.

To know more about Lateral entry examination visit the link below:

https://engineering.careers360.com/articles/what-btech-lateral-entry-eligibility

In general the admission to engineering courses will start as soon as the results of entrances released and its expected to be August,2021/September,2021. For more specific answer I would recommend you to provide your state and which exam you have appeared for admission.

I hope this answer helps. All the very best for your future endeavors!