For 'Render Animation' - you select the start-scene and the end-scene from the drop-down lists - all*** intermediate scenes should be included as possible choices, except obviously the start-list can't include the last available scene and the end-list can't include the first available scene.
For me [on PC] on clicking the button it will first export the OBJ/MTL/Textures and then it opens and renders each scene in the list from the start-one to the end-one, strictly in the order as listed; incrementing the saved image names to suit [always starting with the first one you've given it].
***Leave the 'step' as '1' to get all frames rendered: with the 'step' at a higher value it jumps through the scene list [starting with the first one], which I think is only really useful for doing quick tests - but RS asked for it to be included, so it's there.
The list of scenes available for rendering is always as displayed on the scenes tabs in the SKP, but with any that are shown inside () omitted from the animation, as is the SUp way.
There is no FPS [yet] as it's not supported by the current beta version of Octane - but who knows...
Are you on PC or Mac, how many scenes are listed in the drop-downs - how many scenes are available to animate in the SKP ? etc etc