Stressed about background check

I am terrible at making CVs. I made a CV where, in my work experience, I put an extracurricular project I did at university and a science summer research project, neither of which were paid. In my interests section I put some forage simulations I completed by labelled then Consulting simulation - Company name and thought I was okay because I labelled them as simulations. During interviews, interviewers see that name on the CV and get interested and I clarify that it is a job simulation in case they think it is an internship. I don't know how much people know about simulations but I am worried that during a background check it will come up I only worked at one place listed on my CV and that I had accidentally misled anyone. Though experiences in consulting are not necessary for the role they are desired.
Please explain the background check process in more detail.