If you got your medical recommendation through HelloMD, there is nothing more you need to do in CA in order to purchase products from a dispensary. However, its optional that you also apply for an official state card, which you can do through your local county. You will need to complete their forms, and provide a copy of your HelloMD recommendation to them. Again, this is an optional step and does not grant you any additional privileges. Most people don’t bother with this for that reason.
After the November vote, this may change in that you may also need to do this step in order to be a compliant medical card holder, but this is TBD. Note too, that after the vote in November, there will be a period of time (most estimate around 12 months) before the rules are implemented, whatever they may be.