1. Explain it simply
还 (hái) means 'still' and sits directly before the verb or state.
For an ongoing action, pair it with 在: 还在 = 'still doing'.
To say something hasn't happened yet, use 还没(有): 我还没吃饭 = 'I haven't eaten yet'.
还 never goes after the verb or at the end of the sentence.
2. Show examples
八点了，他还在睡觉。
Bā diǎn le, tā hái zài shuìjiào.
It's eight o'clock and he's still sleeping.
还在 = still doing
我还没吃饭。
Wǒ hái méi chī fàn.
I haven't eaten yet.
还没 = not yet
公共汽车还没来。
Gōnggòng qìchē hái méi lái.
The bus hasn't come yet.
还没 before the verb
3. Share a tip
Keep 还 tucked right in front of the verb or state: 还在睡觉 (still sleeping) and 还没来 (hasn't come yet). Never park 还 after the verb or at the very end.