how to record multiple inputs

Hi Everyone, I'm new to the recording game. I've been recorded in studios on several occasions and now I'm looking to do recording of my own accord. I am a HUGE fan and proponent of the open source community. Ok, so I'm running (what I believe to be the latest release of Reaper) on Windows XP. I am using a Lexicon Omega USB interface to get my sound into the computer. I have recorded with this setup successfully, but am looking to add to my skill. I now want to record multiple inputs simultaneously onto different tracks (i.e. I have put a mic on my guitar speaker cab to my interface, and I am also directly inputted to the interface from my amp head -- I want these recorded as two separate tracks). How can I do this with my resources? Every time I try, I get both the mic and direct input on all armed tracks. Help!!! Thanks in advance for lending some advice to a rookie like me!

It sounds like you haven't told Reaper about the inputs on your interface. Go to the "Options" menu and choose "preferences." From that dialog, choose the "Device" item from the left side. Presumably you're using some type of ASIO driver that came with the interface. Make sure that's selected from the dropdown list. You'll also see directly below that the options to select your inputs (and outputs) for your interface. You choose the range of these inputs - the first and the last. Reaper then knows how many inputs and outputs you have. Now, when you're recording you can choose an input for each track that you create. For example, if you have one track for vocals and one for guitar, you can choose which input from your interface is feeding that track. Choose the input by right clicking on the record arm button at the left of the track control panel. You'll see the option near the bottom of that menu to choose a mono or stereo input from your interface. Good luck, and welcome to the forums!

thank you thank you thank you! 

you were right on the money! Thank you so much!!! I had it mostly right, but did not realize I needed to assign a USB bus for each input. Problem solved! back to work!