The Senate is voting on the $700 billion financial-rescue legislation tonight, and a lot of people are going to be watching it.

Here’s a guide to what’s going to happen on the Senate floor, so you’re in the know when it’s all going down.

1) What time are the votes going to take place?

The votes will probably occur between 8 p.m. and 10 p.m. Eastern time, though that’s an approximate range.

2) Why are there three votes dealing with this legislation?

The first vote is an amendment proposed by Bernie Sanders (I-Vt.), which would impose a surtax on those making more than $500,000 a year to help pay for the legislation. It’s almost certain to fail.

The second vote is needed because the Senate has to consider an existing piece of legislation. So, Sen. Dodd (D-Conn.) is going to propose taking a mental-health parity bill, strip out the text of it, and insert the text of the financial-rescue legislation in its place. Some mental-health parity provisions will remain, though.

(Note: Mental-health parity involves having insurers cover mental-health costs as well as physical medical costs. Sen. Pete Domenici (R-N.M.) has been a major advocate for this bill, and it’s the Senate’s last chance to pass it before he retires.)

The third vote will be for final passage of the bill. Sen. Dodd and Sen. Judd Gregg (R-N.H.) are likely to speak for about a minute each -- possibly before this vote, but almost certainly at some point during the evening. Senate Majority Leader Harry Reid (D-Nev.) and Senate Minority Leader Mitch McConnell (R-Ky.) may also speak.

It's possible that Sen. Reid will seek unanimous consent to have the Dodd amendment become the underlying bill, which would effectively combine votes two and three into a single vote.

3) How many votes are needed to pass the legislation?

Each item needs 60 “aye” votes to pass. Technically the Senate just needs a majority, but a simple majority could be subject to a filibuster. So, 60 votes is a “filibuster-proof” majority, also referred to as a “cloture-protected threshold.”

4) How does the actual vote work?

The first vote will be a simple voice vote, ayes and nays. The latter two will be roll call votes, in which the names of each senator will be read off, and that person will reply with his or her vote. Usually, not everyone gets counted the first time around, so those who didn’t vote will be named again until they get everyone they can.

That also means people will know how each individual senator voted.

5) How is a vote closed down?

Once everyone has voted, the clerk will bang the gavel and announce the final tally. Members are able to change their votes before the gavel falls.

6) What happens if it looks like the bill isn’t going to pass?

Sen. Reid has two options if it starts to look like the legislation won’t go through. He can pull it, which would allow him to renegotiate. Or, he can vote against it himself, which would mean he would be part of the winning side and could be part of the motion to recommit the legislation later.

7) If this legislation passes, what’s next?

Most likely, the House would consider the legislation on Friday. Rep. Barney Frank (D-Mass.) told FOX Business that the vote would likely occur before noon that day.

Also, the smoothest way would be for the House to pass the same version of the legislation, because then it could go straight to President Bush’s desk. If the House and Senate pass different versions, they’ll have to do a ping-pong-style procedure in which they go back and forth, voting and negotiating until they arrive at the same version.

8) Is the Senate version different from what the House rejected?

The Senate version has some differences from what the House rejected on Monday. It includes a proposal to raise the Federal Deposit Insurance Corp. insurance limit to $250,000 from $100,000, a tweak to the Alternative Minimum Tax and some small-business incentives.

In addition, where the House proposal was about 110 pages long, this is 400 pages. Some of that is the mental-health parity wording, but some involves other things, including incentives for wool research, providing wooden arrows for children and changes to the excise tax on rum from certain places.