Adverbs of Place tell us the place where something happens. They answer the question "where?". Adverbs of Place mainly modify verbs. Example -
1. Please sit here. (Where should I sit?)
2. They looked everywhere. (Where did they look?)

Adverbs of Time tell us something about the time that something happens. Adverbs of Time mainly modify verbs. They can answer the question "when?": Example -
1. He came yesterday. (When did he come?)
2. I want it now. (When do I want it?)