If I remember right, the outside wheel bearing is sealed into the rotor/flange assembly. The inner bearing is loose, and will want to fall out when you eventually pull the rotor off. My truck has manual hubs - once I got them off, there's a pair of 54mm nuts and a star washer on the spindle that are holding the rotor on. On the automatic hubs, I think there's a c-clip too, which may be what we're looking at in your pic?
Anyway, download the manual. It's got detailed instructions.
From the looks, your next step is removing the cone washers. They are tricky! They make a cone and point in. The way you get the out is by taking a rubber mallet and "tapping" on the side of the rotor to get them to kinda jiggle loose. Don't lose them.
The service manual will describe. They are a pain.
Also. The warn manual hub conversion makes it so much easier to mess with!