Hi, adilia133, you are not talking to Apple here, and Apple doesn’t reply or post here… occasionally community specialists might post here, but not Apple, Inc. your best bet would be to reach out to Apple support at apple.com/support then their 1-800 number, email or chat… as well, that particular store should have a phone number you can contact them at… however, even though I am a Mac user here, same as you, I can get you started… what year was your Mac mini made? Look on the bottom for a model number that starts with A , then 4 numbers… go to everymac.com and type that into the search function… and it’ll tell you when it was made, if it’s recent, or a later model … this picture from 2018 shows you the most recent ports, eg video out/monitor connection: 
and here’s the m1 from 2020
if you have an older Mac mini it might look like this..
here’s a link from Apple that tells you which Mac Mini has what… Identify the ports on your Mac - Apple Support (CA)
if you have a recent Mac mini, it uses USB-C/Thunderbolt 4 for 4 ports, plus 1 hdmi… so if you wanted to connnect a Dell monitor to it, and it didn’t have a usb-c port on it but instead one of these:
Then you’d need an adapter… usb-c/thunderbolt 4 to whichever one you’d see in that display interfaces chart. Bear in mind, too that your Mac mini will support certain frequencies for output/refresh rate , eg, 24 hz, 60 hz, maybe 30 hz… you should have gotten a user guide for it…,check there for that… also, depending on the model of your Mac mini, it may support up to 3-4 monitors… as per this link from Apple: Connect a display to Mac mini - Apple Support (CA)
anyways, I’ve tried to help you, but I’m in Edmonton, Alberta Canada and you’re in NYC… and I’m replying on my iPhone, and doing this all online… so, there is only so much I can do on a Saturday night to solve your problem… so unless IT or you are willing to pay for my emergency return flight to NYC then home again, plus hotels, cab fare and meals… ( that’d be a ‘NO’) then I’m done here for tonight… call ‘em Sunday morning … that’s it ( man, I miss Zabar’s and fresh baked bagels)
john B
