How can many stars be formed from the remains of one supernova?
Stars don't &quot;come from&quot; a supernova.
Stars come from the interstellar gas in the galaxy, particularly where it is more concentrated into nebulae.
This gas is mostly hydrogen and helium, but it is &quot;enriched&quot; with heavier elements from old stars, including from stars that have exploded in supernovae. Over the billions of years since the galaxy formed, there have been many supernove which have gradually increased the amount of heavier elements in the interstellar gas.
The shockwave from a supernova can cause the gas to become squeezed and more dense, and this can trigger the gravitational collapse that leads to star formation, but the gas for those stars doesn't come from one particular supernova.
As a nebula collapses into many stars, some (the largest) will be large enough to supernovae (which can trigger subsequent periods of star formation).