How does the elephant protect itself from its enemies?

There are a number of things:

• They normally move as a herd, safety in numbers.
• The are large and the adult males normally have sizable pairs of tusks which they can use to chase or gorge an assailant; it can also use its trunk which is muscular and can simply swat away a small assailant.
• As they are large many animals will not even consider attacking them; although a pride of lions will often take down an old or injured elephant or a small juvenile.
• They have a very thick skin, which makes it hard for smaller animals to bit through or even take hold of.
• The Trumpet very loudly.

When an elephant has its ears and trunk up and is running at you trumperting, most sane individuals with simply run!!

In most cases elephants will attack humans when they feel threatened, in particular if a person gets between a mother elephant and her baby.

They will also attack humans if they have been injured, particularly by hunters or if they have "gone rogue.

They will not think twice about charging a car or large truck!

it uses its trunk to wrap the enemies and use its tusk to charge at them chasing them.

Elephants usually walk in groups, and in this case predators like lions or tigers can do nothing against them. But when an elephant is alone, it is attacked by a group of lionesses and lions, in this case there is no chance for the elephant.
Elephants have really good hearing so they may move slowly but because of their hearing they can hear for kilometers when predetors or a storm is going to come that is how they proptect themselves.