Payment made as a guarantor

If I make payment of bank loan as a guarantor in case of NPA. How can I recover the amount from actual loan borrower? The actual loan borrower is a partnership firm. The property which is mortgaged is the common property of the partners and me(guarantor). I have made cleared the entire loan. How can I recover this from the borrowers ie partners of the partnership firm as firm is in losses? Some say you can step in to the shoes of such creditors. I don't know what does that mean. Which is the sure shot and the best way to recover my money?