I am getting some new tubes for my amp, and I want to do a 24-hour burn in. How?

Only mechanical things need a "break-in" period! Tubes and transistors - no! Tubes will of course suffer from "aging" as cathode emissions decline with use - noise increases!

Wire doesn't need "break-in" either! 

Burn in??????!

Tubes sound and perform best during their first 100 hours. Their very best the first 50 hours. They continually degrade after that.

Agree with mapman- why waste tube life- you don't put your car on rollers to bed the tyres in, you just take it easy for a while or end up in a hedge.

Keep a diary of hours and perceived sound if you're that anal unless it's the istant gratification of a bedded in system you're after.

On, no signal needed, 60 hrs, burn-in is done.

I bought tubes from Brent Jesse. 

Did NOT like them. 

He said, ok, finish burning them in, then keep or return them. Top line were his instructions which I followed.

They did change slightly, I still did not like them. I picked another I knew I liked (I had used spares of them), half the price, full refund (I paid return shipping)

Sounded great brand new and GREATER after 40-60 hrs.