Beginner in programming and data science with 100 hours to spend learning the basics
Being good at a subject does not automatically make someone a good teacher, and it looks like Roman's answer on Quora has fallen into a trap of thinking everything he knows is simple and could be picked up quickly. Also making the potential student attempt things outside of a beginner level - effectively just by research on the web following a 2 paragraph pointer - is going to make progress slow and frustrating. Despite no doubt good intentions, the advice there is likely to give a very poor learning experience.

There are full structured tutorials available on free Massive Online Open Courses (MOOCs) available for learning data science topics. These have been put together by professionals who know how to teach, and the effort put into designing any of these courses, providing materials etc, totally dwarfs the effort that went into the advice on Quora.

Ignore the Quora answer, and sign up for one or more of these MOOCs. You can find them at Coursera, Udacity, edX and other similar places. If you want to cram a lot of study into a short time, look for "at your own pace" courses where all the materials are available to you immediately.

The almost canonical start point to test the waters would be Andrew Ng's Machine Learning course on Coursera. Machine Learning is one of the more immediately accessible and fun parts of data science, and the course goes into theory and practice with additional sections for beginners at the start covering necessary maths and programming. Following that entire course is probably around 100 hours total effort. You won't come out of it knowing data science, but you will gain useful practical skills, and get a real taster for the machine learning side of the subject.