How do I lose weight?

This is a picture of me last year, and one from today. I graduated last year, and I played softball all four years of high school. Now that I am in college and have a a job, I am not as active as I was. I go to the gym, but not every single day and I’m not consistent. Plus, I have no idea what exercises I should be doing and what is beneficial to me! In the picture from last year, I thought I was fat. Now, I’m even bigger. I’m so self conscious about this. How do I lose weight? I just seem to keep gaining…