To create an std::unordered_map container in C++, you can use the following syntax:

#include <unordered_map>

std::unordered_map<key_type, value_type> myMap;

Here, key_type and value_type are the data types of the keys and values stored in the map, respectively. For example, if you want to create an std::unordered_map that stores integers as keys and strings as values, you can use the following code:

#include <iostream>
#include <unordered_map>
#include <string>

int main() {
    std::unordered_map<int, std::string> myMap = {
        {1, "one"},
        {2, "two"},
        {3, "three"}
    };

    return 0;
}

This program creates an std::unordered_map container called myMap that stores integers as keys and strings as values. It initializes the map with three key-value pairs: {1, "one"}, {2, "two"}, and {3, "three"}.

Note that you can also use the insert() method to add key-value pairs to the map one at a time, like this:

myMap.insert(std::make_pair(4, "four"));

This will add a new key-value pair to the map with a key of 4 and a value of "four".