Air travel with a 5 month old?

In 6 days my sister and i and my baby will be traveling by air the flights only 2 hours but the thing is after the 2 hour flight we only have a 20 min layover to get to another plane for another hour flight..and the problem is getting off the plane lugging the kid and all the luggage trying to find the right terminal and getting on another plane in 20 mins in a large airport..plus That 2 lift offs and 2 landings..plus 5 days later we have to come back and do it all over again...any tips