Hi and welcome!
Driving to MK means parking in the lot, taking a tram to the Transportation and Ticket Center, then take a monorail or ferry to the main gate. If you're on your first trip, I recommend the ferry first thing in the morning. It's a wonderful way to see the MK, looming in front of you as you slowly pull in to the dock. Many times you'll see a character in a boat alongside the ferry, or waterskiing alongside, or both!
At Epcot and Hollywood Studios, you take a tram to the front gate, if Animal Kingdom is busy, you'll take a tram, but it's usually easy to walk to the front gate.
The trams are always parked at the end of the rows that are currently being parked, so don't worry if they put you at the end of one or the beginning of another. Just be sure to either take a photo of your row, or write it down. All those rows look alike and if you're excited, you will forget where you park.
Don't run to get on a tram, if one is filled and pulling away, another one will be along momentarily especially in the morning.