Chabad.org — English translation + Rashi
Torah Temimah points to Yerushalmi Horayos 1:8 (unit 3; single primary locus per emergency Core plan).
Sefaria — Yerushalmi Horayos 1:8
English: “Their hands” — the hands of each and every one.
Each elder uses both hands — every participating elder performs full two-handed semichah.
Semichah is performed by each elder with both of his hands. The Yerushalmi’s reading of “et yedeihem” insists that the act is personal and complete for every participant; one-handed leaning or a collective gesture that omits an individual’s full contact does not satisfy the requirement.