How do you adjust height if hand grips?

To adjust the height of the handgrip, you'll need to unscrew the wing nut that holds the handgrip in place and move the handgrip to the desired height and re-screw the wing nut in place. You can also find the full instructions here: https://cdn.shopify.com/s/files/1/0240/6504/8681/files/A995.pdf 

Hope this helps!

What are the dimensions when it is folded up? overall length and width at and bottom

The folded measurements are 21” H x 5.5” W x 2” D. Thanks for asking!