First photo--I have a dental pick I can use to remove old seals. This "O" ring shows cracks from age when stretched a little. Match the new "O" ring from the parts kit to the old "O" ring. Coat it with jack oil. Install the new "O" ring.
Second photo--Install the conical metal seal in the hole for the release valve. The pointed end goes in first. Tamp on it with a small screwdriver to make sure it seats at the bottom of the hole. Thread the release valve into the hole.