HOW DO I TURN ON IPENCIL 1ST GENERATION

It does not have a power switch. You simply plug it into the Lightning Port of a compatible iPad and it will pair and charge the Pencil for you. If you aren't getting it to work when you try this, then the pencil may have sat too long with no charge and gotten fully depleted and will not be able to take a charge any longer. The Pencil should be charged periodically to keep the battery from getting fully depleted to prevent this from happening.

When you plug it into an iPad which is compatible with it, it will pair and as long as it is charged, it is on.

This link provides more information --> Connect Apple Pencil with your iPad - Apple Support