I did. I don't know how to do it.

我看了。但是我还是不知道怎么做。

youdao

Can you help me build a website? I don't know how to do it.

你可以帮我架设网站吗？我不知道该怎么做。

youdao

I don't know how to do it. Can you give me some _suggestions__ (suggest)?

我不知道怎样做这件事。你能给我一些建议吗？

youdao

I don't know how to turn it on, I don't know what to do.

我不知道怎样打开，不知道要做什么。

麻省理工公开课 - 媒体、教育、市场课程节选

I don't know how to do it really.

我不知道要多快才行。

麻省理工公开课 - 热力学与动力学课程节选

But I don't do it on purpose, I wouldn't know how to.

BBC: Is it ever right for a therapist to cry?

"We have to find a way out of this, but how we do it, I don't know, " he said.

BBC: Belfast flags trouble: Matt Baggott in warning to rioters