first of all; to begin with; before anything else
probably; most likely; almost certainly; virtually
more or less (satisfactory); on the whole; reasonably
anyway; at any rate; for now (at least); for the time being
先ずは自己紹介をさせていただきます。
First of all, let me introduce myself.
先ずはお茶でも飲んで落ち着きましょう。
First, let's have some tea and calm down.
先ずは現状の把握から始めよう。
Let's start by understanding the current situation.