To seek admission for a B.Tech in AIDS course with a cutoff of 142.5, follow these steps:

1. Research Colleges : Identify colleges offering the B.Tech AIDS program.
2. Check Eligibility : Ensure you meet the eligibility criteria specified by the college.
3. Application Process : Visit the college's official website for the application form and submission guidelines.
4. Prepare Documents : Gather necessary documents like your marksheet, identity proof, and any required certificates.
5. Submit Application : Complete and submit your application before the deadline.
6. Follow Up : Keep track of your application status and respond to any communication from the college.

For specific college details, refer to resources like Careers360