I am experiencing some clipping and popping with my podcasts. I am using the Eurorack UBB1002.

Now, I don't know a lot about mixers - but I put on the headphones, hook it up to Audacity, do the tests and watch the WAVES as it is being created in Audacity and it looks pretty good.
On my mixer, there is a set of lights which indicated blue up to red. It never seems to get to red, yet on Audacity, it is clearly clipping. Not sure what to do, I know tech support for audio is really difficult over the internet. I have not played with the dials on the mixer, just leaving them on the default right now - so maybe that has something to do with it...

Also, the mics are Apex 415.

What are you using for your audio input on the computer side of things - an external interface, sound card, or motherboard sound card? Are you connecting the Main Out or the Tape Out jacks on your mixer to the computer's sound device? On the mixer's meters the middle light, marked "0", is the nominal output level, your signal at the mixer should hover about there. Are you operating your mixer on Battery or AC power?

From the main out RCA to my soundcard on my laptop.

From the main out RCA to my soundcard on my laptop.
That should be okay - I think the Behringer's tape outs are nominally -10dBv consumer line level and most soundcard line level inputs expect -10dBv. Sure you're going to a line level input on the laptop and not a mic input? My Dell laptop, for example, doesn't have a line level input on its sound card at all, only a mic input and headphone output.

Actually you are right, it is a mic input on the laptop...