First learn about von Neumann architectures, learn about functional stuff maybe, just a bit so you will have some foundation
After that you should try solving basic problems, mostly algorithmical, so you will get your mind in shape. Codeforces, Atcoder could assist you here, since to my knowledge at least codeforces has div4, which is begginer friendly. After you will learn to solve algorithmical tasks, you can broaden your skills in OOP and such. Though keep in mind that OOP mostly works well for graphical stuff, for others you should try different paradigms