Please refer to this link for how to make a basic connection:

http://support-remote.splashtop.com/entries/514283-how-do-i-make-my...

I did the basic connection and it starts to connect and the android side says failed to connect

It's because you have more than just 2 audio channels on the remote machine.  Check out my thread:

http://support-remote.splashtop.com/entries/20287612

Rene,

I have the same problem. The thing with me is, mine was working fine until the last Splashtop HD update on Android. That is when I started having "Connect Fail". I have it all set up through firewalls and even used IP and tried using my Gmail. Then I spent a good while looking at what Alex and been going through, and made sure I changed the audio settings on PC and still NO connection. Splashtop, I hope you have a fix soon.

I am having the same problem as JD.  Worked fine and after the latest update, I get 'Connect failed'

Help...

I got an update for my desktop software for Splashtop. Now my Xoom and desktop connect again. I am not sure what they did to fix it, but THANK YOU! Please don't change it again, LOL!

I can not connect with Xoom on verizon 3g network....please repair this known issue

I have a lenovo thinkpad laptop and motorola xoom tablet, when I am home on wifi they find each other just fine, but if I am away from home on another wifi I cannot find my laptop with the tablet. Any idea what I might be missing?

@Glenn,

Please use the feature: Internet Discovery . This following link is an official step-by-step tutorial on how to find your computers under different networks with Internet Discovery:
http://support-remote.splashtop.com/entries/20056888-experimental-feature-find-your-computers-with-internet-discovery