This is the app to learn programming on your phone. I recommend you start with HTML, CSS and Javascript https://play.google.com/store/apps/details?id=com.sololearn
it teaches you stuff, then you have quizes where you can test what you've learned, and you can actually write some code and test it see it working
python is also a good one to learn after javascript
this can teach you basics of becoming a freelance website developer https://www.smashingmagazine.com/2009/07/the-roadmap-to-becoming-a-professional-freelance-web-designer/
some of it might not perfectly fit south africa or khayelitsha but you can imagine how it connects to the businesses around you
perhaps marketing to them is better by word of mouth
sometimes you don't need to build the entire website from scratch - sometimes people just need to get information out there - look at using wordpress to get started - you can pick from existing themes, or upload your own themes where you customise how it looks with some html and CSS code https://wordpress.com/
there might be free wifi at your library
on on the mycity bus
also, if you want to read a website later, the "Internet" app on your phone lets you save a page and read it later. the Chrome app doesn't