first of all

Adverb

idiomatic not-comparable sequence

(sequence, idiomatic) Firstly; before anything else.

Japanese Meaning

何よりもまず / まず第一に / 最初に

First of all, I want to thank everyone who helped with the project.

まず第一に、このプロジェクトを手伝ってくれたすべての人に感謝したいです。

Sense（1）

(sequence, idiomatic) Firstly; before anything else.