Share the game window and it reads your EXP and mesos off the screen: what the hour is worth, how long to the next level, and how the run is going.
Share the MapleStory window and that is all: it finds the status bar itself, reads your level and EXP off it, and shows EXP per hour, time to your next level, and a dashboard of the run. Keep your inventory open — solid or transparent — and it counts mesos per hour too. Full screen or windowed (1280×720 or bigger), sharing the game window or your whole screen. Chrome or Edge on a computer.
Your browser opens its picker on the Window tab: click MapleStory, thenShare. That is the only choice to make. Anything else is caught and you will be asked again. Playing in full screen? If the picture comes through black, the tracker offers to share your whole screen instead.
The lines that say things like “You received EXP (+89)” and “You have gained Mesos (+14)”. It looks for them itself and marks what it finds — if that is right, take it; if not, drag a box around them. Nothing else is needed after this.
The bar says how far along the level you are, not how much that is worth — a tenth of a bar is 3,900 experience at level 20 and over a million at 90. It counts up from here on its own, so this only needs to be right once.
Type it exactly as it appears, separators and all. It learns the shapes once and reads them from then on, so nothing here has to know what your interface looks like.
Nothing leaves this tab. The frames are read in your browser and thrown away; no picture, number or run is sent anywhere. What it learns about your screen — where the status bar is — stays in this browser.
It reads the picture and nothing else. It does not attach to the game, read its memory, see its traffic or send it a single keystroke, and it never will: the moment a tool can act, it stops being a tracker. Your server's staff are the people who say what is allowed there, and this is written so the answer to "what does it do" is short enough to give them.