Come on, don't call yourself a fool.
Since question 1 was answered, I'll do the rest.
2. Open up what is called the d-map editor. it should be found in the same place as the graphics and midis editors. The first thing you do is select which map you want d-map 0 to start on. I assume that you want to start on the first map, so that won't need touching. I also assume that you changed the d-map's attrabute to overworld, or possibly a cave.
As for starting, look for the word continue and type in the screen you wish to start at. Now, go to that screen and press page down untill you see a blue and green squares. The blue square is the spot you appear after a warp, and the green square is the one where you appear after you continue your game, or start you game. Place those squares where you want link to appear. This should do it for that question.
3. Making the enterence to a dungeon is simple. first, build a map with your dungeon, then make a d-map for it. A d-map, if you havent guessed, is short for dungeon map. While the actual dungeon is contained on the map, some information, like where you continue, what the dungeon behaves like(dungeon, overworld, cave), what music is loaded, and maps and such. Set it up the way you want it.
To make an enterence, go the start of your dungeon, place the continue squares like I showed you before, but this time make sure that they are at the very bottom of the screen, in the dead centre and very bottom of the lower doors. If they are anywhere else, link's enterence animation won't look right. Then make a side warp going out of the dungeon to the spot where you are going to enter it. go to the spot on the overworld and do the same, only this time a tile warp, and go to the dungeon enterence.
I hope this works, if you still have questions, you can consult the official quest tutorial for more help, there's a link in one of the frozen topics in this forum.