You need to appear for NDA or CDS exam, NDA if You are 12th Passed and CDS if You are Graduate, The exam consists of Written tests followed by SSB interview and when You qualify the test, Yiu will be called for Training once after successful completion of Training You will be given Full time commissioned in the army and will be given a Rank of Lieutenant in the Army, Please follow the link below for Details of NDA and CDS.

https://competition.careers360.com/exams/cds

https://competition.careers360.com/exams/cds