Hi Pragathi,
As per my knowledge, I don't think there is any feature yet to directly import steps and transitions in Test sequence block from an external file.
But here's something that might help: Programmatically Create a Test Sequence - MATLAB & Simulink - MathWorks India
Using the sltest library you can create and edit steps and transitions of a test sequence block in MATLAB script. You can try importing your data and then use this to create your test sequence block.
Hope this helps!
