Slitherine

What do i need and how can i mine asteroids?

Is there asteroids? I have not seen a star system with them.

If you have any scout ships (any ships perhaps---starting scout ships work fine) with an empty cargo module, take that ship to the star with the asteroids. In the top right, there is your selected fleet box, and on the left of that is a list of commands. The "explore" command should be available, use that, and any goodies that the asteroid is hiding will be captured by your ship and transferred immediately to your empire reserves.

This works with any of the anomaly types I've found, with one exception --- not going to spoil that here (yet!)