How do I say 'how'?

The 怎么 / 怎么样 split is one of the highest-value distinctions for early learners. They both translate to “how” but serve different functions:

• 怎么 + verb = how to [do something]. 怎么去？(How to get there?), 怎么说？(How to say it?), 怎么写？(How to write it?). This is the method question.
• 怎么样 = how is it / what do you think. Standalone or at the end of a sentence. 你觉得怎么样？(What do you think?), 最近怎么样？(How have you been?). This is the opinion/evaluation question.

The idiomatic 你怎么了？is worth memorizing as a unit — it means “what’s wrong?” or “what happened to you?” and is the natural response when someone looks upset, tired, or not themselves. It is about concern, not method.