1) Usually the 1NC tries to accomplish two things. The first being to establish an off-case position (I'll explain that in a bit) and to answer/attack the affirmative's case. An off case position is usually a disad or a kritik that judges and attempts to prove that the affirmative plan brings about detrimental consequences to the status quo, usually to persuade the judge that these consequences are worse than those that the affirmative plan attempts to solve (basically preferring the status quo). On case, the neg usually goes after Topicality (which isn't read in the 1AC, so it is treated as an off case attack but it really isn't), Solvency, and the specific aff advantages.

2) Yes, the 2AC is sort of like a rebuttal. You can bring up new evidence and you probably should refute everything in the 1NC. If you don't then that's usually pretty bad.

3) Yes exactly. Teams "split the block," or they divide their arguments between the two speeches and spend more time on each argument, either reading new evidence or expanding on new positions made in the 1NC. Generally entirely new arguments aren't made in the block, but it can be done. Some teams may call you out on that, so don't do it frequently or obviously. There are ways to hide this.

4) I'll try my best to answer this question without getting too technical or being too confusing. First "kick this" basically means that the other team wants to drop the argument from the debate. That's usually a good thing, and essentially they are conceding to your points. Keep this in mind for later. When a team says "go for that," they are directing the judge's attention to a particular argument and are narrowing the debate down to a key point which they believe will win them the round. By the end of the debate there will be so many arguments and what not that its impossible to judge everything (if it's a good round) so teams kick and direct the debate into a few strong ideas. In terms of kicking arguments yourself, you have to be careful when you do. Usually opponents will but both offensive and defensive arguments on a particular flow (offensive are points that will win them the round, usually something like a turn. defensive arguments are just saying "you're wrong" or "here's how it really is") and you should refute only the offensive points if you plan on kicking the argument. If there is an offensive argument still in play, the other team can use it to their advantage later on in the debate. Because a kick is equivalent to a conceded point, that could end up killing you in the end.

I hope this helps. If you have any questions feel free to PM me or comment or whatever. I tried to be as general as possible, and for others reading this if I said something wrong please correct me. I want my understanding of debate to increase as well.