随便 is tricky to translate but very useful! It’s used to mean however, wherever, or anywhere you like. Check it out!
请随便坐！
Qǐng suíbiàn zuò!
Please sit wherever you like!
我只是随便看看。
Wǒ zhǐshì suíbiàn kàn kan.
I'm just looking.
(literally: I’m looking however I like.)
随便你！
Suíbiàn nǐ!
It’s up to you!
(literally: However you like.)