https://www.marthastewart.com/1528929/memorial-day-flag-protocol-and-etiquetteAccording to United States Code Title 4 Chapter 1, Section 7, "the flag, when flown at half-staff, should be first hoisted to the peak for an instant and then lowered to the half-staff position. The flag should be again raised to the peak before it is lowered for the day. On Memorial Day the flag should be displayed at half-staff until noon only, then raised to the top of the staff."
See later in the article for what to do with a flag that can't be lowered to half staff, like those little ones stapled to a dowel.