Ok I understand the 4 instruments on the front row & the 4 on the back row BUT I have 1234 chairs on the left side & 1234 chairs on the right side - separated by an aisle & 1234 on the back left side & 1234 on the right side. So which 1234 & 1234 do I use - right or left!! The violin will place on the left 1st chair but the drum only places on the right 1st chair. So as you can see I am totally lost!!!

The insturments are widly scattered on the chairs, on both sides of the aisle.
Look behind you when at that 'multi-horned' record player (Gramaphone?) , I think there's a chart on the wall that shows the correct seating of the Zorkestra.
If not, at the bottom of the record bin is one about ohchestras, it can help you figure out the practice room. You need EIGHT of the insturments on the chairs.
And REMEMBER the notes, you will need them in another puzzle later.

Mome, here's what another walkthrough said about placing the instruments:

"Place the instruments in this order in the back row, from left to right: Wertmizer, Gederaglini, Frobophone, Popperkeg. In the front row, from left to right: Violin, Nambino, Miano, Fleezle. When every instrument is in the right place, you hear a clue about the Harmony of the Spheres..."

But my problem is still that I have divided rows of chairs in this room. How are the instruments placed (in order) & on which row of chairs??

Ok, Mome.
Just a little stuck at the consevatory, are you?
Questions:
Have you played the albums on the record player? Have you drawn some pics. of the instruments? You need to Know the pics that go with the sounds. You must also copy the picture on the wall, this is for the Fanfare. I did not Know of WT, for this game, I took a lot of notes. I put them in the little Zork Book, that came with the game. I did not have any notes of the exact location of the instruments in the practice room. I went back and did it agin. Just for you.
The practice room:
There are four chairs in back left, space, then four chairs to the right. The front is the same, four on the left, space, four on the right.
Easy now,
Top left, first chair, Wertmizer(two people thing), skip, skip, then the forth chair is to be the Gederglin thing( two people horn). Now skip over to the top right row of four. Put the big Flebophone thing(big Tuba) in the first seat, skip, skip and put the popperkeg (baton thing)on the last seat on the right. Now you can go and to the left front row in front. On your left first row, first seat, put the violin, skip, skip and then put the drums(Nambino) on the last seat of the left row. Right front row. Frirst chair is the to be the Miano(Lyra like strings), Skip ,Skip and finish on the right, last chair with the Flezzle( flute like).
Best Always,
Rick