I would love to know too. I applied to the Summer Bound program for July thinking I could go, but I got a competitive internship at the National Institutes of Health and can’t skip work. I had to decline my acceptance 
However, I can go to the STEM Summer Program for sure. Is there any link I can go to? I want to apply to it ASAP.
This is all I see when I google the STEM Summer Program: https://admissions.dartmouth.edu/visits-programs/dartmouth-bound/stem-exploration-program