The filter table is the table you will use mostly, if you're using iptables to build a firewall. If you want to use iptables to do network address translation, then you'll use the nat table. The mangle table isn't used too often in a typical firewall setting (used to modify packets).
*filter says, that all that comes afterwards applies to the filter table. It has an INPUT chain for packets coming into the "inner box" of your machine, an OUTPUT chain for packets leaving the "inner box", and a FORWARD chain for packets that are forwarded elsewhere (they don't come from or leave your "inner box").
Your current firewall rules state, that your machine is completely open: A pure
-j ACCEPT as the only rule in every chain. The
[0:0] are counters, and mean, that no packets have arrived or left or been forwarded so far.