Solving Systems by Reducing Matrices: Homogeneous Systems

Let A be the reduced coefficient matrix of a homogeneous system of m linear equations in n unknowns. If A has exactly k nonzero-rows, then k n, Moreover,

if k < n, the system has infinitely many solutions, and

if k = n the solution has a unique solution (the trivial solution) Consequently, a homogeneous system of linear equations with fewer equations than

unknowns has infinitely many solutions Trivial solution is when all the unknown is equal to zero

please explain this in detail with examples pleaseeee