あります for things, います for living beings, where things are with に, and position words.
あります for non-living things, います for living beings (people, animals).
あそこに ぎんこうが あります。
There is a bank over there.
へやに ねこが います。
There is a cat in the room.
Both mean “there is/exists”. Choose by animacy: あります for objects, plants, events; います for people and animals. The thing that exists is marked with が.
に marks the location of existence: 机の上に 本が あります.
つくえの うえに ほんが あります。
There is a book on the desk.
The place of existence takes に (not で, which is for actions). Position words combine with の: 机の 上 (on the desk), いすの 下 (under the chair), 銀行の 前 (in front of the bank).
When the thing is the topic, use は…に あります: 銀行は 駅の前に あります.
ぎんこうは えきの まえに あります。
The bank is in front of the station.
Two patterns describe the same scene from different angles: place に N が あります (introduces a new thing) vs N は place に あります (tells where a known thing is).