See if you want to take admission in BTech course in any of the trade, then you have to qualify an entrance test. Now there are three kind of entrance and I am stating them below:

• National entrance like JEE MAINS and Advanced which provides admission to NIT, IIT, GFTI's and some private colleges also accept this score.
• State level entrance exam are entrances that provides admission to the state government colleges and private colleges in that state. Some of the popular names are MHTCET, KCET, OJEE, WBJEE etc
• Private colleges like Manipal, VIT, SRM also conducts there own entrances. By qualifying those entrance you can apply for BTech in the corresponding institute.

For entrances you have to score good and on the basis of your rank you will be awarded the seat or opportunity to get admitted in the colleges of your choice.

To know more about BTech and entrances visit the link below:

https://www.careers360.com/courses/b-tech-bachelor-of-technology

To know more about Computer Science and Engineering visit the link below:

https://www.careers360.com/courses/computer-science-engineering-course

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