The easiest way to stake token is to visit explorer.livepeer.org/transcoders.
This will display a list of active and candidate transcoders on the network, along with the prices they are charging, and some useful stats.
You can stake to the network by clicking “BOND” next to your chosen node, and then follow the instructions.
It is your responsibility as a token holder to research transcoders based upon their past performance, statistics, rates they are charging, and any social campaigns that they’ve posted indicating why they believe they will do a good job for the network.
Click on any transcoder to view their on chain statistics. Visit this forum thread to view campaigns that certain transcoders may have posted.
When you have selected the transcoder you would like to delegate your stake towards, return to the explorer and click the “bond” button using your Ethereum enabled browser (Metamask, Parity, Mist, Toshi, Cipher, etc). It will ask you how many token you would like to bond, and have you confirm an Ethereum transaction.
Remember that you can always change who you are bonded to or unbond if you don’t believe the transcoder is doing a good job, but when you bond, you have to wait for the multi-week unbonding period before you can withdraw your token.