Explain why the big dipper appears to make a complete rotation around polaris in 365 days?

The stars themselves do not move. (Well, they do, but so slowly that nobody can notice it over a lifetime.) The stars APPEAR to rise in the east and set in the west because the Earth itself is spinning like a top.

The North Pole Star, Polaris, is positioned - by a fortunate coincidence - directly over the north pole of the Earth's rotation. So Polaris does not appear to move (much). Because of the way the Earth is spinning, the stars near Polaris appear to spin around Polaris! So the big dipper and the little dipper appear to make enormous circles in the sky centered on Polaris, going around once per day.