best way to elevate shooting platform by 3 feet?

[bob]

I'm asked to shoot a school's show in a community center's ballroom.

There is a stage that's 3 feet higher than the rest of the room.

I prefer to shoot at eye level, so I have to find some way to raise my
tripod and my seat.
I can put the tripod on a folding table, but how do I raise a chair by 3
feet while remaining safe? How would a professional videographer do it?

[Rich Brown]

One platform for the tripod and another --close but not touching-- for
the videographer. And don't use a folding table for either; you need
something that won't shake.

Post by bob
I prefer to shoot at eye level, so I have to find some way to raise my
tripod and my seat.
I can put the tripod on a folding table, but how do I raise a chair by 3
feet while remaining safe? How would a professional videographer do it?