Steps need to he follow while investing in ELSS

I am having demat account with zerodha and want to invest in ELSS platform.

  1. Could anyone can tell me what are the steps nees to be follow?
  2. what are the things i should take care/ should understand before investing in ELSS?

I have seen the video clips and read about it but still i want to know if could have miss something…

Thanks & Regards,