an attic (storage type only)should be insulated at least with R 28 (min) insulation.Depending on your location , R 32-40 is even better. The insulation need only be resting on the attics' FLOOR only, NOT in the roofs rafters.VENTILATION of the attic is a MUST, by allowing outside air to enter at the soffit/eaves, and exit at or near the ridge.Make sure the insulation does not block the entry of air at the soffet.
The amount of venting is ;for every 300 sq ft of attic floor area there should be AT LEAST 1 sq ft of venting split between 50 % soffet, 50 % peak.) The more the better.(1 sq ft = 144 sq inches.
Eg; an 900 sq ft attic would require a minimum of 3 sq ft of vent , or 1.5 sq ft of soffit vent and 1.5 sq ft of ridge vent.
A continuous ridge type vent is best, but high, near the peak mushroom type vents are also good.