This video discusses in detail how mRNA vaccines work. It's a simple concept, really. Our natural mRNA works with ribosomes to manufacture proteins. These vaccines insert mRNA that codes only for the spike protein of SARS-CoV-2. The spike then triggers the immune response in the body. This creates T-Cell and B-Cell memory for the spike proteins if later a real virus gets into the body. mRNA disappears in 24 hours, while the spike proteins degrade in 36-72 hours. The 2nd shot usually gives a bit more of a reaction in the host. For me, I had 24 hours of discomfort which included fever, chills, headache, fatigue. Then it disappeared fast.
She uses the term 'authorized' and not "approved" because these mRNA 'vaccines' are only being allowed under Emergency Use Authorization. They have not been through the standard approval process which requires much more rigorous testing and and much longer study/monitoring period.
The slight on words is not picked up by most people