Honestly, it seems to be quite unlikely that you can get all the missing functionality working until tomorrow ...
But if you are further interested in a solution here is some example(!) code for a line following robot:
https://www.electronicshub.org/arduino-line-follower-robot/
Remember that those who set up the test environment have made it more difficult by
- switching between black and white lines (on white or black background)
- using a grid of lines instead of one simple line
- removing some of the lines rather than providing a complete grid
You wrote that your robot has six sensors to read the line color (black/white) ... Are they mounted like this:
So the sensors (color red in the sketch above) are paired and two
- in front to detect if the robot is "crossing the line somewhere"
- two at the center left and right to detect when you are centered to a crossing?