The 7 planets are written into the center of the chakra: Saturn in the very center, the other planets on his left (Jupiter), right (Sun/Mars), top (Venus) and bottom (Moon, Mercury). These squares are also assigned to the 7 weekdays.
The weekdays correspond to the native's birthday. The sign of Lagna is another point of importance, e.g. for the health of the native.
The 12 Rasis are placed around the planets (see chakra).
The Sanskrit letters are placed in the empty squares (see chakra).
The letters correspond to the name of the native or the subject of the query.
The picture below shows the complete Sbc.