A shield made of Mana is superior to a normal Ki Shield when you need to block elemental energy or Mana attacks. To make a Mana Shield, move some Mana into your torso and and shape it into a ball through visualization. By using visualization, expand it so it surrounds your body. If you intersect it with the ground it will be stronger since it will draw a little energy from the ground at all times. You can Ki if you need to defend against Ki attacks, but trying to keep Ki and Mana in the same place without one turning into the other is very difficult.
Just like a Ki or Jing Blast, make a ball of the energy you want to use (in this case, Mana) and then visualize Ki moving into your arms and shoot a quick burst of Ki out of your arms so it shoots the Mana Ball.