hmm an adventure mode player overwhelmed by fortress mode...
kinda funny since im a fortress player whos overwhelmed by adventure mode.
but i personally think that the best way to play fortress mode is to learn by starting an easy fortress.
i recommend generating a new world with very low natural savagery, low number of cites, low number of beasts, and frequent ores.
generally the opposite of what you want when playing adventure mode.
look for an embark with multiple shallow metals and multiple deep metals, very deep soil, and clay is a bonus, i prefer to embark in a place with it even though ive never used it.
if you find sand on your embark thats great, green glass can be made out of just sand and fuel and can be used for a number of useful things. sand cannot be seen from the embark screen unless you have a certain plugin, i forget what its called though. (it could just be plain df hack)
since your new, just hit embark now, its a good enough start and you will end up better than if you had carefully prepared to embark since your not used to fortress mode.
now heres something from when i was brand new to df and i had no idea about LNP, the fourms, or even the wiki.
there are 3 things that you need to do IMMEDIATELY upon embarking, #1 build a plump helmet farm, #2 build a still, #3 build a craftdwarves workshop.
plump helmets are an adequate food supply for absolutely any fortress ever, most players end up with a situation where they have plump helmets occupying entire Z levels of filled barrels in their fort.
the still makes booze, it turns plump helmets into dwarven wine as well as make plump helmet spawn (the seed) your dwarves need booze to operate, dwarves are mad drunken bastards who work better the drunker they get, and they will only drink water if its life or death, and even then they wait till they are about to die to give in and drink water.
the craftdwarves workshop can be used to make stone or wooden pots, which can hold more stuff than barrels and are lighter. you cant make booze unless you have an empty barrel or pot, and your food will rot if left out in the open, but will stay fine indefinitely if kept inside a barrel or pot.
i also highly recommend that you disable aquifers and set your population cap to something small, like 20 or 30, its a lot more easy to learn if you only have 30 dwarves to mind.
if your using LNP there is an option for both of those
oh, and whatever you do, DO NOT MINE THE BLUE METAL UNLESS YOU ARE PREPARED FOR INSTANT FUN