overloaded 'operator+' must be a unary or binary operator error

You want to do either:

// Member function, performs (*this + right)
Point operator+ (Point & right)

or

// Free function, performs (left + right)
Point operator+ (const Point &left, const Point& right)

You made the operator a member function, meaning it actually has three parameters when you include the implicit first this parameter.

Either:

• Use *this rather than p1 and get rid of that first parameter, or
• Make the operator overload a free function (instead of a member) — this is preferred.

It sounds like you have declared your operator as a member function. A member function takes an implicit first parameter, meaning your operator now takes three parameters. You can fix this by making it a non-member function.

In any case, it is preferable to declare it as a non-member, to ensure symmetry between the LHS and the RHS of the operation.

As for std::move, it is in the <utility> header. Although I can't see the reason to use it here.