Calathea Orbifolia loves a warm and humid environment. Water it regularly, around once a week (but less in winter) and fertilise once a month in the growing season. Calathea can be sensitive to hard water and chlorine, so ideally try to use rain or filtered water where possible.
When watered with tap water, the edges and tips of Calathea leaves can be damaged by the chlorine and other elements found in it. Ideally use rain water or filtered water to prevent this damage though letting tap water sit out for a few days can help somewhat instead. If this isn’t the cause then very dry air can cause browning tips too, try using a pebble tray or moving your plant to a more humid room like the Kitchen or Bathroom!