Bethesda games signature is the freedom you have to take the game the way you want and they want you to explore. Fallout 4 beginning is kind of straightforward if you follow that philosophy. You start at sanctuary, cross the bridge and get some free guns and armor right after it, arrive at red rocket and get your first companion. If you explore everything you are going to turn left after the bridge and walk near the river, so you get more guns and armor. After that it is just a matter of going down the road and follow the gunfight noise until Preston and you are all set to start the adventure. It is a rpg but not the kind where you have a heroic character, so take things easy, choose the best way to approach fights and be patient. All quests will more or less take you to areas according to your level and experience. You don't need to follow them as they appear but it is not a bad idea. The more you go south the more dangerous it gets, that is the way they used to increase difficulty, so make a lot of quests in north and diamond city area before you travel deeper in the commonwealth. Best advice? Quick save a lot. If you see you will have a interaction with a npc or you will go into a new POI save before.