Rezidanstaki apartman daireleri modern döşenmiş; alt katta spor salonu ve yüzme havuzu bulunuyor.

In Turkish, when one noun describes another, the first noun stays bare (no possessive or case ending) and simply acts like an adjective. Then:

• apartman = “apartment” (modifies the next noun)
• daireleri = daire (flat) + plural -ler
  • 3rd-person possessive -i (“its flats”)

So apartman daireleri literally is “the flats of the apartment [building],” i.e. “the apartment units.”

• döşemek = “to furnish”
• Passive stem: döşen- (“to be furnished”)
• Resultative/passive participle: -miş → döşenmiş (“furnished”)
• modern remains invariable, acting like an adverbial adjective here.

Together modern döşenmiş means “furnished in a modern style.” It’s a reduced relative clause: “[apartments] that have been furnished modernly.”

kat = “floor/storey.”

• -ta = locative case (“at/on/in”).

So katta means “on the floor.” Adding alt (“lower/bottom”) gives alt katta = “on the lower floor” (i.e. the ground floor).

Both var and bulunuyor can express existence, but:

• var is very neutral and colloquial: spor salonu var = “there is a gym.”
• bulunmak literally “to be located” is slightly more formal or descriptive.
• bulunuyor is the present-progressive form, giving a sense of “is located/existing.”

In a marketing or descriptive context (like talking about amenities in a residence), bulunuyor feels more polished:
“alt katta spor salonu ve yüzme havuzu bulunuyor.”

• yüzmek = “to swim” → noun form yüzme (“swimming”)
• havuz = “pool”

When you have an activity noun + an object noun, Turkish usually just puts them together without linking vowels or additional endings. So yüzme havuzu = “swimming pool.”