how do i activate the 'Frame Freeze' after filling the heart up on the top right
That heart has nothing to do with time freeze - it's just the meter for FMC pleasure, once it's full, she will cum, making her less sensitive to your interactions for some time
To use freeze frame, first make sure you bought such camera upgrade, once the camera upgrade is present, during the night simply tap/click the timer itself, NOT red circle on the left of the timer, NOT the "end" writing on the right of the timer, just the timer
Cheers