Serviio

after closely following the guide on how to install serviio on an ubuntu environment,

i started the program 'serviio start/running, process 30679' ... is that it?

where do i store the video?
how can i watch streaming videos to my tablet (ipad/nexus)
and how do i stream videos to my iptv and devices ?

Have you gone thru the steps in Quick Support: Getting Started?

This will show you how to assign profiles for your TV's and other DLNA equipment, and how to share folders.

For the iPad, you will need a DLNA client such as 8player. The Generic profile should be OK for this, however if you cannot play media with AC3 audio, search the forum for my posts and you will find a profile for the 8player that addresses this.
For the Nexus, look at the excellently reviewed ServiioGo from will - see viewtopic.php?f=17&t=6803

thanks

also, please forgive my ignorance. but after running the application and included the videos in the libary.
how do i view/stream from it?

so how do i view the videos from my PC? what applications do you usually recommend to use?

It's not to view it on your PC (although you could di it, with XBMC UPnP client function), you should see the server on your devices connected to the network (iPad, TVs, BR players, etc)