RSR files are no longer used by Poser. The RSR was a proprietary format used by poser for thumbnails. It's no longer supported. PNG files are used for thumbnails in poser starting with version 5.

As for tutorials each of these steps below would each constitute a tutorial of it's own. I've covered this process in webinars. They're probably posted someplace on YouTube.

As with all things Poser there are many ways to do whatever you're trying to do. Here's a rough outline of four figure creation techniques in Poser

=== The Modern Way ===

1. Model the figure in an external modeler such as Blender. (The Sculpt)

2. Export the OBJ at Poser scale which is much smaller than Blender. 400:1 or so.

3. Import the OBJ into Poser

4. Take the figure into the Setup Room

5. Load a skeleton that's similar in dimensions to your new figure

6. Adjust bones' positions as necessary. Add or remove bones as needed. (Rigging)

7. In Pose room edit weight mapping to achieve proper bending (Weight Mapping)

=== Slightly Old School ===

1. Sculpt the model as above

2. In the Model define all the body part groups using the Poser naming scheme which is WEIRD. (Cutting up the figure)

3. Import the grouped OBJ into Poser

4. Spawn props from the OBJ with the grouping tool

5. Use the Hierarchy Editor and [Apply Standard Hierarchy] and then [Apply standard rotations]

6. [Create New Figure] on the Hierarchy editor

7. The figure is created in the "New Figures" folder of the library.

8. Load the "New Figure" and adjust the joints with the Joint editor as needed

=== Really Old School Method ===

This method does not work for weight mapped figures

1. Sculpt and group the OBJ as with the slightly old school method. The shape needs to be vary close to the "donor figure"

2. In a text editor open the figure's CR2 file.

3. Edit the 2 OBJ references to point to your newly created OBJ. (Hacking the CR2)

4. Open the newly hacked figure file in Poser and adjust joint as necessary

=== The Old Timers Might Remember This One ===

Does not create weight mapped figures

1. Find a copy of PHIBuild.exe (Good luck)

2. Use Phi Builder to create a PHI file for your figure.

3. In Poser File > Import Heir File ..

4. Adjust the joints on the created figure.

These are rough outlines there's way more to rigging a character. The easiest way is the modern way.