先…然后【xiān … ránhòu】

先 marks the first action and 然后 brings in the one after it. 先 is an adverb, so it sits after the subject and right before the verb. 然后 starts its own clause.

先 goes after the subject

English "first" can open a sentence or close it. 先 does neither: it goes between the subject and the verb.

• × 先我洗澡 → 我先洗澡
• × 我洗澡先 → 我先洗澡

A new subject after 然后

然后 comes before the subject of its clause, so the second step can belong to someone else.

Past events

然后 narrates what already happened as well as what is planned, so it's the one to use when telling a story. 先…再 also means "first … then", but it stays with plans and instructions.

More than two steps

A longer sequence keeps adding 然后 and can close with 最后, "finally".