おっとー! みそはまだだよ!
Whoa! Don't ^put in [add] the "miso" [soy bean paste] (just) yet!

 おみそ汁の具、何がいい?
What kind of ingredients do want in your "miso" soup?

 キャベツ!
Cabbage!

 そう。じゃ、キャベツ刻んで入れよう。
OK. Then, let's chop up some cabbage and put it in.

 かつお節も入れられるよ。
We can also add some dried bonito flakes.

 ここに昆布入れて。
Put some kelp in it.

 ほら。もうちょっとで沸騰するよ。
Look. The water is about to boil.

 火を止める直前に、みそを入れるのよ。
We put in the "miso" [soy bean paste] in right before we turn the stove off.

 お玉にみそを取って。そこでみそをスープの中で溶かすのよ。
Take some "miso" [soy bean paste] in the ladle. Then let it dissolve in the soup.

 また、火を付けよう。
Let's turn the stove back on.

 沸騰してる! 昆布を取り出そう。
It's boiling! Let's take the kelp out.