2.5 gallon set up

Question
I inherited a 2.5 gallon tank from a friend two years ago (pentagon shaped; about 12 inches tall and 6-8 inches wide). I most recently had four fish-- two tetras and two little algae eaters (none bigger than about an inch). Last week my landlord turned the heat on in my apartment without warning and it got very hot. All four fish were killed-- including two that I had for over two years. :-(

I cleaned out the tank and am going to replace the old gravel, but keep many of the old parts. However, I have never set up an aquarium from scratch. Most websites give instructions for bigger tanks, so I have a couple of questions.

1. I usually guessed as to how much dechlorinator I added to the tank because the instructions were always for larger tanks. Should I change the amount (more or less) for a new tank?

2. How long to do I need to let my tank sit before adding fish?

3. How many fish should I add at first. Can I add four at once? (FYI- I like having at least two algae eaters as they keep things nice and clean.)

Any other tips would be great, as I want to avoid another massacre. Thanks!

Answer
To answer your questions:
1) Keep using what you have been using.
2) I would let it sit at least 2-3 days
3) For such a small tank I would only add one at a time.

Your tank is actually over stocked. The standard rule is one inch of fish per gallon. Although I am well aware rules can be broken and things work out well.
Once you change the gravel and set everything up just add the dechlorinater and let it sit for 2-3 days and you should actually be good to go. A lot of websites make setting up an aquarium a much larger project than what it really needs to be.
Once you get your first fish wait about a week and go ahead with the others.
Happy fish keeping!!!