The Senate District 46 Convention, including the 46A endorsing convention, is at Saint Louis Park High School, 6425 W 33rd St, St Louis Park, MN 55426. More information can be found on the DFL Senate District 46 website and Facebook page.
A full explanation of the subcaucusing process is available on page 4 of The DFL Official Call. The video to the right and below break it down into more understandable chunks. Here is both a website and application, available for Android or Apple, called SubCalc that helps calculate the number of delegates a subcaucus receives based on the total number of attendees.