What did Ezra stand on as he read the Law to the people?

Answer: A high wooden platform

Ezra stood on a high wooden platform built for the occasion, and when he opened the book all the people stood up.

“Ezra the scribe stood on a high wooden platform built for this occasion. At his right side stood Mattithiah, Shema, Anaiah, Uriah, Hilkiah, and Maaseiah, and at his left were Pedaiah, Mishael, Malchijah, Hashum, Hash-baddanah, Zechariah, and Meshullam.”— Nehemiah 8:4 (BSB)