Pick a first map
Dust II is the clearest starter. A site is reached by Long and by Catwalk, also called Short. B site is reached by Tunnels or Mid Doors, with an elevated Window. Mid runs from T spawn toward Double Doors, and a higher path leads to Catwalk. Tunnels split into Upper and Lower. Grenades do not pass through the roofed tunnel ceiling.
Say the place name when you die. Long, Cat, Tunnels, and Mid are enough for teammates to rotate.
Second and third maps
Inferno funnels fights through Banana toward B, and through Apartments or Mid toward A. Banana is contested from Coffins and Van. A defenders use Pit and Balcony.
Mirage is won through mid. A entries are Ramp, Palace, and Connector. B entries come from Apartments toward Van and Kitchen. The Window and Nest look over mid.
Nuke stacks A above B. Routes include Hut, Squeaky, Ramp, Secret, Outside, and Garage. The radar changes floor as you change level. Vertigo is a high construction site. Terrorists can smoke toward B from spawn windows, and the outside edges are kill zones.
Full mode availability is on each map page. Unranked Competitive uses Mirage, Nuke, Dust II, Vertigo, Seaside II, Train, Cache, Overpass, and Inferno. Seaside, Cobblestone, and Fallen II are Casual. Poolside is Deathmatch only. Seaside and Seaside II are kept out of the same Casual vote, and playing either keeps both out of the next two votes. That restriction is tied to update v1.5.9.7.
Radar and clutter
The HUD prints the sector name under the minimap. Radar zoom in settings runs from 2 to 5. Map Details can be turned off to drop heavy props if your frame rate falls. Textures return on the next match when you turn the option back on.
Maps that are not in the public pool
Aztec left the defusal pool in v1.5.9.5. Agency and Office belonged to Hostage Rescue, which is not a standard public mode now. Metro, Barcelona, Royal, Fallen, Season, and Greece have also been removed from official rotation. Corrupted Mirage and Gust II were event variants. Dizzy was used for Flying Scoutsman. Do not wait for those in a normal Casual vote.