Rank plates and symbols

I know that this is an amateur move but I have a very important question to ask. I know that each time you level up to a certain point you get a new plate that's one color, on that plate is a symbol and a number and there's a number next to the plate. What do this all mean and how can you tell what rank you are from this information? I see some posts where people state that they are rank or level 2132 and wonder how. I know that I'm no where near that and probably won't be for a long time but I would like to understand what it all means. I am a wanna be gamer who is still learning and taking baby steps so please be kind with your responses 🙂

I'm just a person who loves playing games online or on any console because it helps relaxes me and it keeps the mind sharp.