Hii.. 

As you ask process of admission admissio in diploma courses.. I didn't mention the name of University College Institute where you want to get admission kindly mention the name of same so we can get easily and answer you properly.

All the best!!

Greetings Eahtasam,

For taking admission in Diploma,You need to first check which colleges offer Diploma in your preferences.Then try to identify the mode of admission wether they take admission through any exam or through direct contact with College.
1.If you appear for any Exams all over India then try to identify the cut off and prepare accordingly. If selected then you need to go through Counselling procedure where there is maximum chance of finding a better and getting better Colleges. As most colleges take admission through any exam.
2.If not Selected in any exam,dont be disheartened contact every possible college talk about your Current Scenario,they might give you a way to take admission.
NOTE: Please check the college internaly and externaly as well and also the stream they are having or not.

Good Luck!!
Regards Ankit!!