Thinking of unionizing my workplace need advice.

So like the title says, I'm thinking about starting a unionization movement at my job and am wanting advice on how to do this. I work in a small chain of retail stores in Illinois similar to Blain's Farm and Fleet. I'm wondering if anyone knows of a pre existing union that might cover workers like us, or if I should look into forming a new union from the ground up. Forming a new one seems rather intimidating given the resources needed to do that.

Also what level of management makes it to where one is no longer included in a union? I'm technically a manager, but it's mostly just a title and a fuck load of extra work for no extra power or pay.