You just need to login to SteemEngine.com - you should already see some PALcoins given to you or (if you haven't looked before) a blue icon in the top-left of the screen to claim coins been allocated to you. Then stake some (or all) of them to start earning more of them through posting and curation.
Apart from using the palnet tag, you don't need to change any other behaviour, unless you wish to start posting directly from the PAL site.