sign pdf doucment  with digital signature multiple times using java api

Our web  applications generates a pdf using jasper reports, Our users download pdf from our app sign it manually and then scan and upload  it, we want to move away from this and use digital signatures.  The generated pdf must be signed by several   users , I want to try adobe livecycle java api   to sign my pdf, please advice if are there any tutorials for this and is there a trial version   I can use   ,download link  etc. pelase advice.