Adobe Flash and Steam for Linux (Ubuntu 12.04.2 64bit)

I'm using Ubuntu 12.04.2 x64

first of all
1. after OS install check and install all official updates
2. if you have nVidia based GPU activate "NVIDIA accelerated graphics driver (**experimental** beta) (version experimental-310)" in "Additional Drivers" application which can be easily found with ubuntu dash (12.04 versions only, for 12.10 it's a bit different)
3. reboot
4. open terminal and type:
wget http://repo.steampowered.com/steam/signature.gpg && sudo apt-key add signature.gpg
5. also type:
sudo gedit /etc/apt/sources.list
at the end of file add two lines:
## steam
deb http://repo.steampowered.com/steam/ precise steam

save the file and close gedit
6. in terminal type:
sudo apt-get update
sudo apt-get install steam

if u get some dependency error mentioning libgl... (this comes with early version of ubuntu 12.04.2 x64)
type:
sudo apt-get install libgl1-mesa-dri
and after that you should be able to install steam
sudo apt-get install steam

after installing steam start it from desktop or from ubuntu dash
it will start some download from repo
after that you will be prompted to type steam username and pass.
7. after successful loging in steam quit steam application

8. download latest 32-bit tar.gz package of adobe flash for linux from adobe official download location

9. extract only one file from tar.gz
libflashplayer.so
copy it to
/home/<username>/.steam/steam/ubuntu12_32/plugins/

<username> is your home directory

10. start steam again and you should have videos in steam store.
if you have some problem with sound in steam store first check if these videos are muted if its not you will have to quit steam again and in terminal type:
sudo apt-get install libasound2-plugins:i386

11. start steam again and you should have videos with sound in steam store.

hope this will help anyone :)