Try googling for some advice. There are countless people before you who asked the same question on CF, quora, etc.

Well , First Before Starting Solving at Codeforces :

1-Start Solving problems in website Called a2oj and click in ladders and Solve Problems in Egyptian Olympiad in Informatics it has Good Problems for Beginners

2-After You solve Problems From Ladder Start Solving Some problems in website Called uri It's very Good For Beginners

3-Once You see You Can Solve problems Well So Start Solving Problems in Codeforces From problem set and sort it to solve the easiest problem.

4-There's Junior Sheet.....Read about it in PDf in Description and then start solving from it https://www.youtube.com/watch?v=DZ6YTtILCE8&t=2s But Videos are in Arabic but Materials are in English....You can See Videos From youtube That has the same name : example if there's Video of Dynamic Programming But in Arabic Then You Can Open youtube and search About Videos in English have same name

5-After you see that you Solve A problems Well Then Start to participate in Contests in Codeforces

6-You Can Read Competitive programming 3 book or Competitive programmer's Handbook...This books are good for you.

7-If you have any question or There's Something You Can't Solve Problem and need help ask here and don't care about downvotes.

8-Try searching if you stuck at thing First.

If You have any Question or need any help you Can reply on this Comment and ask me :)