Getting access to Steam Broadcasting:
1. Open Steam client
2. Got to File -> Settings -> Account
3. Find "beta participations" and select "Steam beta" in drop down menu
4. Steam will ask to restart. do so (if not - do manually).
5. After the update, go to File -> Settings -> Broadcasting
6. Set up preferences as you like
Setting up quality/prefrences/privacy:
By default, broadcast mode set to "Friend request" ie. you start streaming if some of your friends request it and you accept request. As far as I know, picking up option "Anyone can watch my stream" and visiting your own page in browser will activate public streaming for all.
In order to see if you qualify for particular quality/bitrate settings you need to know your channel/line specs. If you have no idea what it is, best simple way to do is:
1. Visit SpeedTest.net
2. Select the nearest big city (capital preferable)
3. Select any provider or particular that rings the bell and start test
4. See what is your upload rate it
In order to stream at best quality @ 3500 Kbps (Kb/s) via Steam you need upload rate close to 4Mbps (Mb/s) ideally. Again, this is not a simple question, but let's just assume that 1080 at max quality available is 3500 Kb/s. if your upload rate is 1700Kb/s (~1.7Mb/s) then it would make sense to lower the resolution and bitrate (altho, not necessary for resolution), otherwise it won't work or will be dropping stream every few seconds.
How to watch:
1. Browser -
Any web-kit based browser from last few month will work
IE9 works too if I recall correctly
2. Steam -
or just visit
profile of a friend who is streaming to select stream
(YOU NEED TO BE LOGGED INTO STEAM TO USE BROADCAST FEATURE)