Use the word "otherwise" to talk about something that's separate from what you previously said.

For example, you can describe the consequences of not doing something:

You definitely need to put together a will. Otherwise, if you pass away, your family will have to deal with a bunch of complicated legal hassles.

You can also use it to describe one characteristic of something that's different from its other qualities.

She gets pretty pissed off when people show up late for meetings. Otherwise, she's pretty easy-going.