I don't have a great answer except to say that this is probably not a "do-it-yourself" home mechanic type job. If you really want to attempt it, buy or download the shop manual and/or a repair manual, you are going to need it.
That said, don't replace it unless you really need to, there is no defined replacement interval for the chain and it has been known to last for more than 400,000 miles. Only replace if it is making unusual noises or a visual inspection shows excessive wear.
timing chain
Lucky for you, the 2001 Toyota Corolla comes with a timing chain and is good for the life of the engine. No need to change it.
timing chain.
timing chain
If you mean Toyota Corolla it has a timing chain. No maintenance is required.
It depends on the mechanic or stealership.
Timing Belt.
yes
Yes, it does.
The 3.0 liter V6 engine in a 2001 Toyota Avalon has a timing BELT
V6 has a belt and the 4 cylinder has a chain.
No. It has a timing belt.