How do I insert an element into a dictionary?

A Dictionary<TKey, TValue> is not meant to sort its items in a specific order. Instead, it uses a key as a quick way (O(n) in Big-O notation) to retrieve a specific item.

Inserting an item at a given position is a list's feature.

Maybe if you describe your issue more precisely we could show you some workarounds.
We would need to know why you need insertion, i.e. the details of your implementation that lead to this requirement.

This is one of the way to add element in Dictionary,
Dictionary<string,int> dict = new Dictionary<string,int>();
dict.Add("Bat",1);
dict.Add("Ball",2);
dict.Add("Stump",3);

This is one of the way to retrieve element from Dictionary,

foreach(Dictionary<string,int> values in dict)
{
console.WriteLine("Key is {0} and value is {1}", dict.Key,dict.Value);
}