Image Formation by Lenses: Convex Lens

CBSE Class 10 Physics Chapter 10: Light – Reflection and Refraction.
How are the images formed by the convex lens? How can we locate the image formed by a convex lens for different positions of the object? Are the images real or virtual? Are they enlarged, diminished or have the same size?
This is demonstrated with the help of an activity with the help of a screen and candle flame.