To me, it looks like everything except for "remember to only kill all ships except one small ship."
No offense to the poster, but it looks like someone thats been playing for maybe a month or two tried to explain how to chain to someone thats been playing for maybe two weeks.
This is not how you chain, and chaining isnt an exploit. If anything it would be nice to have in the guide section if its not already there.
Chaining is mostly done in 0.0, doing it in higher sec is possible but kinda pointless tbh. Its usually not done in anything above 0.0 because in higher sec theres usually people that go through random systems killing rats, and 1 stupid person can !@#$%^&* up your entire day's work on getting a system wide farm going.
But, I guess you could find a remote 0.1-0.3 system people may not normally goto. I know a couple that are dead ends and have no stations that people usually stay out of so whever I wanna rat in high sec I usually go there and I have a bunch of secure cans anchored in a safe spot to keep ammo and loot in.
Anyway heres how you chain:
First off find a system that only you, or your buds are likely to hunt in and make sure they all understand whats going on. If you dont make sure they understand what to kill and what not to kill, its gonna end up in a !@#$%^&* up mess.
Once you have a system you want to farm, go through the belts. Rats in belts only spawn once you get to the belt, they arent persistant even though it may SEEM like they are. Once you, or anyone in the game gets within a certain range of the belt, rats spawn. This may be why the original poster thinks you have to mine to get them to spawn
while in reality, mining a roid has nothing to do with rat spawns.
Once you have gone through all the belts go back to the top one and see what has spawned there, if nothing has yet, goto the next belt and give that belt a bit more time. Also, make sure you go down the list of belts and dont just randomly go from belt ot belt, it doesnt affect the rat spawns, its just easier on you that way to remember what spawn is where.
Once you have a belt with rats in it, make an opinion on the rats. Judge their bounties compared to what you know can spawn there. ie: If you a spawn consisting of 3 battle cruisers ( @ maybe 250k each ) and 2 frigates (@ maybe 25k each), would you want that or would you rather have something better say 2 Battleships ( @ 1.2m each ) and 3 cruisers ( @ maybe 90k each ). If you would rather have a different spawn, COMPLETELY KILL OFF THAT SPAWN. Do not leave anything alive. Loot if you want to, or dont, it doesnt affect the spawn.
If you want to keep the spawn you found at that belt, kill all of the bigger things, ie: if you kept the spawn I mentioned above w/ the battlecruisers you would kill the battlecruisers and leave both frigates. You can kill 1 of the frigates, but I personally wouldnt waste my time and just go on to the next belt.
If you were to have a spawn that consists of 3 battle ships and 2 cruisers. Kill the battleships and leave at least 1 cruiser.
Always leave at least 1 ship standing if you want to keep the spawn.
Do this through all the belts. Keep what spawns you like, kill off the ones you dont. Eventually if you get lucky with your spawns, you can get a system of say 9 belts each with spawns of your liking. I have had a system where 5 of the belts had a spawn of 3x 1.8m battle ships, so me and my bud just went to each of the belts and killed the spawns cept the frigs and then by the time we got to the 5th, the 1st was usually respawned.
However realize that if you farm, you have no chance what-so-ever to get an officer spawn. Unless you get lucky and when you kill off a spawn and it spawns. You cannot chain officiers, they wont respawn as the officier, but as a normal rat.
Although you cannot get an officier, you CAN get a faction ship. Ie: Dread Guristas / Dark Blood / etc.
You CANNOT chain them though, after you kill them, they will respawn as a normal rat. And what I mean by you can get them, is if you have a Blood Sage ( normal blood cruiser ) you kill and next time it respawns, it has a chance to respawn as a Dark Blood Sage (faction blood cruiser). However it will not ever respawn as an officier ( Officiers are named rats like a real name like maybe... Teshuj Tault or somethin... )