I did download this free e-book: https://www.packtpub.com/packt/free-ebook/learning-python and I did let me guide to some extent by it months ago. This was before I stumbled over the sololearn app.
The content of the book was so wide organized that I had difficulties to remember a lot of it. I will take it a second time in the near future and deepen my knowledge with it.
Jump right in, if it requires previous coding language knowledge it is recommended that you learn that first.
If you want fuller knowledge I recommend you use a secondary website that teaches other aspects of Python as Sololearn covers most of the main parts of coding languages they leave out some aspects.