Weigh in whenever you like — the same time every day makes the comparison the most reliable.
The day you actually weighed in. It defaults to today; you can go back to fill in a day you missed, but not forward. One value per day — logging the same date again overwrites it.
In kilograms, up to two decimals (e.g. 72.35). Weighing at the same time daily is the most reliable — ideally after waking and using the toilet, before eating.
Body fat percentage — copy what your scale shows, or leave it blank. Bioimpedance scales are noisy, so read the long-term trend rather than any single day.
Note anything that might explain an odd number that day — salty meal last night, poor sleep, a hard session, a carb-load day. Up to 255 characters.