Here are some ways "otherwise" is used:
* To express an alternative: "I need to finish this report today, otherwise I won't meet the deadline." (Meaning: If I don't finish the report, I will miss the deadline.)
* To express a consequence: "You need to take your medicine, otherwise you might get sicker." (Meaning: If you don't take your medicine, you might get sicker.)
* To introduce a different possibility: "I'm not sure if I'll go to the party, but I'll let you know otherwise." (Meaning: If I decide not to go, I'll let you know.)
Examples:
* "Please be quiet, otherwise you'll wake the baby."
* "We'll have to cancel the picnic if it rains, otherwise we'll have a great time."
* "I'm going to the store, do you need anything? Otherwise, I'll be back soon."
In short, "otherwise" is a word that helps you to introduce a different scenario or a consequence of something not happening.