Jahir
Freedom from self-incrimination
The freedom from self-incrimination means that you cannot be forced to testify against yourself in a criminal trial. The amendment that provides for this right is the 5th amendment, like with miranda rights.
Now just when can I use it?
It can be used during police investigation or during a trial when the answers the person gives could potentially lead them to getting criminal charges.
What is this immunity stuff i've heard of, I just got arrested
It grants immunity from a charge if a person gives testimony for a trial, it nullifies their immunity from self-incrimination though.