While not a Steam-native game, similar visual novel guides can offer general navigation tips for this style of interactive game. Steam Community or help with technical installation A Complete Walkthrough + CG, Endings, and Achievement Guide
Core components
Once the meter turns yellow/orange, switch to the "Action" or "Mouth" icons. New sub-options will appear that weren't visible at zero arousal. Position Swapping: Ffhc Kasumi Rebirth V 3.1