Nice man, reminds me of a particular artists work, you should check him out, he goes by Slinkachu. I will link one of his books that I have: https://www.amazon.co.uk/Little-People-City-Slinkachu-foreword/dp/0752226649
Yours is a technical question. I don't about online tutorials, but I can recommend the excellent book titled Sculpture as Experience. It will give you a strong foundation of different sculptural materials and methods.
Wow, as soon as I saw this, I thought, "This looks like the work of Andy Goldsworthy." I have one of his books, "Stone", it's likely the best coffee-table artsy book I own!
Look through some books. Sculpture Today has been a really useful contemporary sculpture reference for me.
What are you interested in making?
I really enjoy Tom Friedman's work. Reading this really gave me a lot of insight about how an artist can use everyday materials to explore the space around him. Pretty cool stuff.