How do I pair a 2nd gen pencil with a 8th gen iPad I can't get working .any help would be greatly appreciated

You can’t. The Second generation Apple pencil is not compatible with an 8th Generation iPad.

See: link-> Apple Pencil compatibility - Apple Support

Yup,

Like everyone has stated the 2020, 10.2 inch screen 8th gen iPad uses the 1st gen Apple Pencil with the silver chromed, metalised top and magnetic cap.

You got the wrong version Pencil.

You can't

You need a first generation pencil