Question: Maple Physics -Tensors: how to derive acceleration in spherical coordinates

I think the Maple Physics package has the promise to revolutionize the teaching of physics. Two recent tutorials have been very helpful (“Vectors in Spherical coordinates using tensor notation” and “A Complete Guide for performing Tensors computations using Physics”).   Unfortunately, despite these, I still have problems even when trying to use it for simple things. No doubt this is primarily a sign of my limitations. However, in the hope that others might share this, I have the following question.

As an exercise, I would like to use the Maple Physics Tensor notation to derive the expression for acceleration in spherical coordinates – identifying Coriolis force, etc.  I can’t get past the first step – how to define the tensor dx/dt.   That is, how do I write the time derivative of the Maple space coordinates [X].  I assume that this can be done in about 3 steps, if someone would be kind enough to humor my ignorance. Thanks in advance.