Just guessing but will try to help.
The opening will accept some type of fitting, maybe a basketball needle, but more likely a tapered plastic nozzle of various sizes, they may have left out of package? But, you need an air supply for sure. Hand pumping will keep you busy til Xmas.
Send a close up picture if you can, we have the tapered nozzles we do not need them and we have a nifty compressor we just got at Home Depot.
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