8th Grade History and The Bailout

It's been a long time since I took a class in Politics. Though a buzzer went off when I heard that the Senate will be voting on the Bailout on Wednesday.

I thought one of the purposes of the House was to filter stuff first and that the Senate never voted on things unless it was approved by the House.

So if the House voted it down, how did it get to the Senate?

House->Senate->President if Veto back to Senate for 3/4 majority in order for it to pass.

Maybe I'm wrong but would like clarification.