So, first your immune system is instructed to create the protein that resembles the covid virus protein.
Your immune system recognizes that this is foreign and on their own the T cells create antibodies to fight it.
The Instructions to create the protein are destroyed, so there is no left over stuff to tell your immune system anything.
The second dose goes in and the new set of instructions to create the protein do their job. The antibodies you have from the first dose see the protein that is created again and attack. The result is some effects from your immune response and the antibodies that were created after the first dose. The instructions are again destroyed. You have even more antibodies now, and they all know what to do, and everything else with your immune system is as it was before the shots. Nothing left to do anything other than a set of antibodies left behind to fight covid.
That’s the gist of it.
The key item is this:
“ After the piece of the spike protein is made, the cell breaks down the mRNA strand and disposes of them using enzymes in the cell. It is important to note that the mRNA strand never enters the cell’s nucleus or affects genetic material. This information helps counter misinformation about how mRNA vaccines alter or modify someone’s genetic makeup.”
http://www.cdc.gov/vaccines/covid-19/hcp/mrna-vaccine-basics.html
Got it?
The rest is ignorant hogwash.