If you cut wet grass and put it in bag/barrel you will get wet silage out which will be acidic ,low in protein ,dry matter which will need more for an animal to get enough food value out of it , will cause sloppy dung and if inside on straw will use more . Basics are you need grass leaf not stalks /stems /seed heads , as dry a standing crop as possible , cut on a sunny day to maximise the sugars to aid fermentation then allow the grass to dry by spreading as thinly as possible to help dry quickly and evenly then ensile as quickly as you can and seal to keep out air . Not sure where you are but in the uk but the time to get dry silage has about finished