Please contact your child's school to learn more about classroom assignments. My daughter's school doesn't share this information with parents until a couple days before school starts, and then they post it on classroom sheets outside the school office (there isn't an email or letter sent home to parents about classroom assignments). Contact your child's school to learn their process and timing for announcing which teacher each student will be assigned.
The teacher(s) may also provide school supply lists the first week of school. In the meantime, you may use the grade-specific supply lists that Education.com compiled as a general guide of the supplies your son will need.
I'm including links below to SchoolFinder, which includes contact information for U.S. schools, as well as the Back to School info center, which includes the school supply lists and other tips to help prepare for the new school year. Thanks for asking!