Better not count on me, because I don't have the Yongnuo flash. And a little hands on experience is always a good thing. It is good to have seen it work once.
The 568 manual is online though (rougher read because it is not text searchable). It's page 48-49 explain the slave modes.
There are two extremely different cases:
S1/S2 are simply optical triggers. They only will do manual flash mode, where you manually set the power level in the flash to be correct flash exposure for the current picture. This is NOT point&shoot flash, Manual means YOU, who will need an understanding of Manual flash. This is easy, not hard at all, but requires a bit of learning effort on your part. It is not point&shoot.
Says S1 is simple optical trigger, it simply flashes with the first flash it sees, which is from some other
Manual flash mode flash, which the camera triggers however it can. That could be the camera internal flash, so long as it is in Manual flash mode too.
Says S2 ignores the first flash and triggers on the second flash. This is for trigger to work with
iTTL flash, for when the camera iTTL flash mode is the trigger. Slave ignores the first preflash, and triggers with the second working flash. The Yongnuo is still manual flash mode. Seems sort of a pointless combination, if using the manual slave, set the triggering flash to manual too (so you will have some control in S1 mode). S2 is really more for simpler cameras, which only have point&shoot, and have no Manual flash mode.
And it has Sn slave mode, which is extremely different. This N is compatible with Nikons
Commander (which the D7000 has one), and is same as REMOTE mode in a SB-700 (for example). This does Nikons Advanced Wireless System (AWL), which can include doing multiple remote wireless TTL flash. All commands and menus (like the TTL menu) are in the camera Commander menu. The flash becomes a simple Remote, following Commander signals. All controls are in the commander menu. See
Using the Nikon CLS Remote Wireless Flash System about learning the Commander.
Camera settings are really not a function of these slave modes. Sn TTL is still automatic flash, and S1/S2 are still manual flash.