How do I know where Tiles are starting from?How to make responsive background across various devices?Actually I mean if starts from (0,0).There will differences between multiple devices
All tiles in Tiled are relative to the top left 0,0 corner, but that doesn’t mean you have to start the camera at that point. How your game handles different resolutions is up to you, not Tiled.
In my games, I handle responsiveness by defining minimum and maximum areas that can be shown on a screen, and some area between these is chosen and zoomed appropriately based on the screen aspect ratio. This way, wide screens can show a slightly wider area while tall screens can show a slightly taller area, without showing too much of the scene to the player. I design the maps such that everything important to the player is visible within the minimum area from their current location, but that there is enough content to fill the maximum area.
I define these areas in-engine since they are the same across all maps for a given game, but I sometimes add boxes in Tiled to preview them so I can design the maps accordingly. If you want responsiveness handled differently for different maps, you could define these areas as Rectangle Objects in Tiled and load them in per-map.
Similarly, you can also define completely custom player or camera starting positions, movements, etc per map if you want to, using some Objects (e.g. Points) in Tiled, and interpreting them when you load the map.
Thank you so much.