Sololearn teaches the basics. Definitely, you have to look for other resources on the Internet or start working on serious projects to make your skills perfect and job-oriented as well.
For example, I suggest you continue your studies on web development (HTML, CSS) on w3schools.com
Sololearn is great for learning the basics and getting started with programming. Afterwards, you'll want to ruthlessly further your studies by finding more resources to learn from and by practicing what you learn. Practice and running into problems will teach you the most.