How can I change the first commit?

Question

git

In the first commit, I forgot to put the files in gitignore, now it's the 20th commit.
How can I get out of the situation so that I can push a branch to the repository without unnecessary files?
What could be the solution for this?
Is it possible to change the first commit and so that those that came after it were already without extra files?

Answer 1

I understand that you need this https://help.github.com/articles/remove-sensitive-data/

Answer 2

Remove files from git index (git rm --cached).
Add them to .gitignore.