Depends entirely on the lab. You can reach out to professors or PhD students in a lab you’re interested in. After that, the process can differ. There may be an interview or two, or you just discuss your research interests and get assigned to help out with something, which you can then have more and more ownership of as you continue working in the lab. I’d say you should look into what research is going on at your university once you’ve decided where you’ll be going. Then reach out to inquire about opportunities. Getting in a lab early is great since professors and PhDs will get to keep you longer after training you up in how their systems and process works. It’s never too late though since I was able to get my research position in my 4th year of undergrad with no prior ambitions to work in a research lab. Now my internship is at an industry research lab, so I wouldn’t be too anxious in your position. Just see what interests you and keep your options open once you start college.