Here, you have a very flexible towel with a grid pattern printed on it
If you squish the towel, the gridlines will squash closer
In the absence of mass energy, the gridlines are geodesic in flat space time (only the spatial component) thus all objects free falling will travel along those gridlines (the grid itself is infinitely fine, but for the sake of clarify it is not drawn)
Now when something it put into it, the geodesics are modified so that the object free falls towards it, but they are just travelling along the gridlines