Ubuntu :: Switching From UFW To Iptables

So I've used UFW for quite some time now and its been great. But I'm thinking its time to take the plunge into iptables. I want to start blocking repeated connections from IPs trying to brute force my SSH.

I've been reading up on iptables, and it doesn't seem too bad. But I have a few questions I'm hoping people can help with.

1) If I've been using UFW, do I need to do anything special to switch to iptables. I was just going to do "ufw disable". But do I need to uninstall it, or something special. Because even when I do ufw disable, there are still lines in the iptables talking about ufw.

2) regarding those lines, do I need to get rid of them? Is there a way to revert the iptables back to default? These are the lines.

Code:

3) I've read some things that the order of rules in the "chain" matters, but I don't fully understand it. Does it just mean that whatever comes first within the chain takes precedence? So does that mean that if I want to add a new rule, I can't just add it, but I have to make sure it gets listed in the right order?

4) I don't fully understand what these "chains" are either. I can kind of understand the three main ones, INPUT, FORWARD and OUTPUT. But then ufw seems to have added a lot of other ones. What are those?

5) again on chains, if I add a drop IP to the INPUT chain. From my understanding it prevents it from connecting to you. Do I need to put it in the forward chain also? Or just worry about the input chain to prevent connections to me.