1. Explain it simply
都 means 'all / both' and sums up a subject that already includes more than one person or thing.
It goes AFTER the subject and BEFORE the verb, just like 也.
2. Show examples
我们都是老师。
Wǒmen dōu shì lǎoshī.
We are all teachers.
Subject + 都 + verb
他们都喜欢喝茶。
Tāmen dōu xǐhuan hē chá.
They all like to drink tea.
都 before the verb 喜欢
爸爸和妈妈都在家。
Bàba hé māma dōu zài jiā.
Dad and mom are both at home.
都 sums up two people joined by 和
3. Share a tip
都 needs a plural subject to point back to - you can't say 我都 for just 'I', since 都 is summing up more than one person or thing.