How to make the name of a type predicate available for a template?

I have just started to learn C++'s templates using Bjarne Stroustrup's "Programming Principles and Practice Using C++" (second edition). In chapter 19.3.3, during the process of implementing a vector, the writers introduce the concept of concept as follows:

... We call a set of requirements on a template argument a concept ... In C++14, we can make that explicit:

template<typename T>        // for all types T
    requires Element<T>()   // such that T is an Element
class vector {
        //...
};

This shows that a concept is really a type predicate, that is, a compile-time-evaluated (constexpr) function that returns true if the type argument (here, T) has the properties required by the concept (here, Element) and false if it does not.

In another book written by Bjarne Stroustrup ("A Tour of C++", second edition, chapter 6.2.1), the writer gives a similar example:

template<Element T>
class Vector {
private:
    T* elem;    // elem points to an array of sz elements of type T
    int sz;
    //...
};

However, this time the writer states:

... C++ does not officially support concepts before C++20 ...

I tried to run above code (in Visual Studio 2022 using C++20) but it seems that the identifier Element is undefined (C2061). I wonder if Element (and many other concepts stated by Stroustrup in the books) is defined in the standard library? How could we make the name available to use?