I'd just feed the pup IN the crate. one: give your 2 yo as much the same attention/schedule as you always have. Two: read up on dog's roles with one another & how they communicate -Body Language(there are some good books in the library) Three: don't punish your older dog for growling/don't pick up the pup.
As hard as it might be, I'd do more ignoring the pup/leave pup crated & let pup watch you & older one interact/play/train/massage whatever you normally do. The pup is learning smells, sights, sounds, your routines, & as much as you can introduce step by step, you'll get better results. Do the pup training when older is elsewhere. The more your older dog experiences the pup being in its crate the better. It wouldn't hurt to wait for 3 - 5 days before you let them interact. Tthat may seem unneccessary, but if there is any negative incident
then you'll have to regress.
the older may pin the pup, if pup gets too rowdy, but that is normal & nothing to get excited about. I've heard that some folks will get a towel & have the pup sleep on it for a day or 2 then bring it home for the older dog to get used to its smell. also having them meet in a neutral place.
just tossing out my .02, am sure others will have some ideas to share
some feel that 2 of the same gender won't work, but I've had no probs with 3 females & 3 males. They do have their pack order. Ours are all spay & neutered. let us hear