Admission to Osmania University is done through the OU-PGCET exam, and admission is based on rank. In general, admissions to M.Tech programs in India will be based on GATE scores.
Entrance examinations for Osmania University will be held in Telangana State, and you will be able to join the course based on your rank in the relevant subject and the availability of seats.
One of my cousins is a part of the M.Tech degree, and as per what he mentions, you can have access to two main aspects, which are,
You can have details about the admission during the month of april or may, according to what is to be published by the institutional board. For better, and clearer information about the same, it is best that you visit the main website of the institute.