Can the average person please explain to me the process of purchasing and installing a SIM card. Below is my situation and equipment.

I own a Galaxy smartphone that I bought through Tracfone, It works fine and does everything I want. I add data, minutes, and text as I need it. I thought the process of buying and using the Reolink Go was going to be simple. Install the Reolink app and use it to download the Reolink Go information and thats it.

Can you explain why I have to buy a SIM card and pay another phone company other monthly fees. But please, tell me the entire process.

Thank you,