Ok, Thanks Ann, you have the 130D, the arms you have are also the 130D arms and they are fitted correctly, when first opening snap the locks on the short section of the arms, this is the first position, then push the arms to the side slightly to move them out of the arm holder, you can then extend the arms and look them back on themselves holding the hood fully open, at first the hood should lift near to vertical, once the arms are in position the hood will fall back a little, when closing simply lift the hood again to take the weight off the arms, you then collapse the arms back to the first rest position then snap out the small arm locks before totally closing the hood.
Lubrication of the arms pins is possible, use a small amount of silicon grease. apply it and wipe it back off, CAUTION VERY IMPORTANT. do not get silicon or Vaseline into the aquarium water column as it will kill skimmer action for a considerable time frame.