How to ask if someone has to do something

Question

recently I've been talking to some japanese people and came across a problem that might sound stupid but I really had troubles expressing what I wanted.

I know the different forms to express obligations, it's been a while and I have no problem using them when I need to talk about what I have to do, however, I've found myself in a really stupid situation when a japanese friend asked me something about a game, and I wanted to say something like :

After you do this, you will have to do that.

But I had no idea how to express this kind of "obligations".

【～ないといけない】, 【～なければいけない】, 【しなくてはいけない】 etc. just sounded wrong to me...

In this kind of moments I stress and panic it really frustrates me not knowing something like that, so I end up speaking gibberish and changing the topic which makes me look like a complete idiot

So I would like to know how to express this sort of obligations in the third person, and how to ask someone what he has to do?

Thank you!

Answer 1

I, a native speaker, would panic, too, if I had to use one of those "textbook phrases of obligations" to say something as casual as "After doing A, you gotta do B." to explain something about a game. I would sound like a robot if I used any of the three phrases you listed.

What many native speakers would say to a friend in this kind of situation would be so much simpler than J-learners would think. We would use phrases such as:

「Aをしたら、Bをするんだよ。」

「Aをした後{あと}でBをするの。」

「Aをした後{あと}でBをするの。わかる？」

「Aをしたら、次{つぎ}にBをするんだよ。」

「Aをしたら、次{つぎ}にBをするんだよ。いい？」

Answer 2

How about the following

Aをしてから、Bをしなくちゃ

Aをしてから、Bをしなきゃ

～てから emphasizes the chronological order better than ～て and しなきゃ or しなくちゃ are the informal of しなくて.