As you may expect, coming from others continents to Argentina by air you would have first to fly to Buenos Aires.
International flights are mostly directed to Ezeiza International Airport Ministro Pistarini, an hour away by taxi from Buenos Aires in a sleepy Sunday afternoon, that may become more than two hours at busy time.
The best way to town is to take a taxi, booking it at the official stall inside the airport, paying there and asking for a receipt.
Someone will show your way to the cab you booked, carrying your suitcase and forcing you to leave him a tip, but at least this is the only unnecessary expense and now that you are warned you can hold your suitcase tight and save the money.
Expect a good queue when finally at the passports control, at least you may don't need a visa to enter the country and you don't have to pay any duty unless you belong to a country that asks money to poor fellows like me coming to visit it. Quite rightly Argentina government issued a "reciprocal duty", intended to charge only foreigners coming from those countries where a duty is due to enter.
You can also read an interesting post about Buenos Aires with great photos and some ideas for a Sunday afternoon