In the US, this is one of the two things that the government has messed up big time. There is just no excuse of the lack of planning and failed process to get the shots. None. Some areas around me are a real mess. I signed up once, maybe twice, and never heard a thing. Saw a notice about signing up via the county, and within hours I had an appointment. THAT is how it should work but it seems hit or miss. The process is highly dependent on people using the Internet to sign up, which is a real problem for older people who do not use, or cannot use, that technology...
My county has handled this perfectly.
Once you figured out HOW to sign up. The jab site is well organized and efficient. As it should be. This is NOT rocket science....
But be thankful we are not in the EU. The EU has so messed up the vaccination process that it is criminal. Pure incompetence.
Later,
Dan