It's pretty good that you already have a decent experience about the stream in which you want to do MBA by studying during graduation. Now to continue with your passion you need to prepare for one of the MBA exams (CAT, XAT, CMAT, CET etc.)

After getting a good percentile in the MBA exam you can apply for various top reputed colleges like IIMs, FMS etc. Few of the top colleges for doing HR are XLRI Jamshedpur, MDI Gurgaon, Narsee Monjee, Mumbai etc.

Then there is a whole procedure done by the college to make a merit list to call students for next round of interview and WSAT which is based on your aggregate score made by your complete profile (Academic records, work experience, MBA exam's score). Then you go through the second round and again a final merit list is made which is used to give admissions.

Anyway, that's a long procedure of which you should not be worried right now. You should only concentrate on cracking big exams like CAT and XAT with a very high percentile as it is a very high competitive exam.

All the best for your preparations. Work hard!!