Hey, I love it that you have been reading through everything!!
Your weight relative to your height is well within the healthy range, but in order to tone up you need to lose fat and build a bit of muscle. The key to this is eating a clean and healthy diet with lots of fresh vegetables, and exercising regularly. Incorporating some strength training into your workouts will help a lot.
If you follow the plate guide below for your main meals; have something nutritious such as oats with fruit and yoghurt, or an omlette with loads of veges for breakfast; and snack on things like fruit, yoghurt, nuts, crackers and sticks of carrot and celery with hummus and salsa; you will be well on your way to getting the toned look you are after.
Do you know what your current fat % vs muscle % is? In your situation I would measure progress based upon your fat and muscle %s (if you have reliable scales that can do these measurements OR do you know someone that can do skinfold testing using body fat calipers?) otherwise simply using a measuring tape can be effective to monitor progress.
Hope this helps! x