Is the distance you walk equal to the magnitude of displacement
No, the magnitude of the displacement is the distance you are away from the point of origin (or where ever you are measuring from). Say I walk 2 miles North from my house, and one mile South after that. I have now walked a total distance of 3 miles. However, I am only 1 mile away (due North) from my house. So the displacement magnitude from my house to me is 1 mile. The total distance I have walked is 3 miles.