Hey soophie! I started the PhD a few months ago. You will probably find, as I am at the moment, that you'll try out a few systems of collating/organising materials before you find the way that really suits you, so don't worry too much at this stage. Be vigilant with keeping a running bibliography (use Endnote, if possible), try to keep a journal of thoughts/ideas, things you've done each day (though this is a great theory, it's quite difficult to keep going!). You will end up going through material that actually turns out to be useless, but that's all part of the filtering process and locating your topic. You will probably find that the initial topic you go in with will change the more you read. This is perfectly normal--mine has already evolved four times so far! Have fun!