Position in Japanese is expressed as a noun — 'the top of the desk', not 'on the desk'. That is why relative position uses the の pattern.
Also known aslocation wordskoko soko asokoue shita maeposition japanese
“[Thing] は [place] です” states the location of a thing or person.
でんわは にかいです。
The telephone is on the 2nd floor.
Here です means “is (located) at”. The topic is the thing or person; the place comes right before です.
In the textbooksMinna I, lesson 3
Say where X is relative to Y: X は Y の ［position word］ です.
ぎんこうは としょかんの となりです。
The bank is next to the library.
かさは テーブルの したです。
The umbrella is under the table.
レストランは スーパーと びょういんの あいだです。
The restaurant is between the supermarket and the hospital.
Position nouns combine with の: Y の うえ (above/on Y). Common ones: うえ (on/above), した (under), まえ (in front), うしろ (behind), なか (inside), となり (next to), みぎ／ひだり (right/left). “Between A and B” is A と B の あいだ.
To do an action at that spot, use で (the action-place particle): 駅の 前で 待ちます = “I'll wait in front of the station.”
In the textbooksGenki I, lesson 4