Commencer avec ou commencer par ??

Commencer par -- to begin by.... This is used when one starts with a certain action which is the first of a series of actions.

Commençons par ouvrir nos livres. -- Let's start by opening our books.

Then there is commencer à or commencer de. They mean the same and differ only in register, with commencer de belonging to a slightly higher register of language.

Il a commencé à chanter à l'âge de 7 ans.. -- He started singing at age seven.

Commencer avec is, according to the source below, incorrect.

https://www.lefigaro.fr/langue-francaise/expressions-francaises/2017/11/12/37003-20171112ARTFIG00021-commencer-avec-ne-faites-plus-la-faute.php