JOEL - The Prophet Joseph Smith sent the instructions to the Saints for building temples on 25 June 1833. He told them at each end of the assembly hall there would be four levels each having three pulpits. Each level was to be one foot higher than the level in front of it. Elevated seats flanking these pulpits were to be occupied by visiting officers; each one opposite his respective grade. The Nauvoo and Kirtland temples followed this pattern.
The four temples built in Utah during the last third of the nineteenth century have the same seating and elevated pulpits as were found in the Nauvoo and Kirtland temples. The pulpits in the St. George Temple bore initials on each level as had been the case at Kirtland and Nauvoo. The Kirtland and Nauvoo temples placed the Melchizedek Priesthood at the west end and Aaronic at the East end. The Logan, Manti and Salt Lake Temples had them switched and did not have letters on the pulpits identifying the specific occupants of each level.
In 1833 the Prophet specified the following concerning the use of the pulpits(The interpretations of the letters on the pulpits are undocumented but they appeared in an official publication of the Reorganized Church in 1953):

Melchizedek Priesthood:
1. Presidency of Church:
MPC=Melchizedek Presiding Counsel
PMPH=President of Melchizedek Priesthood
2. Bishopric:
PMH=Presiding Melchizedek High Priesthood
PSZ=President of Stake of Zion
3. High Priests:
MHP=Melchizedek High Priesthood
PHPQ=President of High Priest Quorum
4. Elders:
PEM=Presiding Elder Melchizedek
PEQ=President of Elder's Quorum

Aaronic Priesthood:
1. Presidency:
BPA=Bishop Presiding over Aaronic
PAP=President of Aaronic Priesthood
2. Priests:
PAP=Presiding Aaronic Priest
PPQ=President of Priest Quorum
3. Teachers:
PTA=Presiding Teacher Aaronic
PTQ=President of Teachers Quroum
4. Deacons:
PDA=Presiding Deacon Aaronic
PDQ=President of Deacon's Quorum

References:
Regional Studies in LDS History: Ohio
History of the Church Vol.1