A great place to start is the MolSSI tutorials.
Go to: https://education.molssi.org/resources.html
In the top bar you should see Programming in red. The first of these is the "Python Data and Scripting Workshop" and is a good thing to start with.
Later you might want to try the others in the Programming section since they're quite useful.
The Molecular Modeling section (click on it in the horizontal bar and it should turn red) has computational chemistry related tools. (We won't need these for now but for future reference, it's there!)