I disagree with the "cats must be caged" tip from the poster above. Wait until your first catsplosion, then you'll have plenty of meat for the butcher!
I'd agree with the above. Once you've got 1.5 to 2 pages of pets/animals on the animals tab (press z for your fortress status), building butcher shops and then butchering every new foal/kitten/puppy/calf that gets born is a GREAT way to do things. It keeps you well-stocked in Bones for Crafted Goods, Skins for Leather and Bags, Meat for food preparation, and Fat/Tallow for other stuff.
However, that being said - it may be a bit much to take in / pay attention to all the alerts as a new player, and it IS simpler to just build one cage and assign pets to it.
I would highly advise doing a search on 'Catsplosion' and 'Meat Industry' on the Dwarf Fortress Wiki for more info there. Dealing with Catsplosions IS important to learn about as a newbie, because it can kill your framerate.
On the embark site side, I can make a few suggestions that might help.
1st, dont look for rivers near the ocean. For some reason, I've found they often end up being saltwater.
2nd, look for Brooks instead of Rivers. Brooks are listed in the info screen to the right if they are present. It will say something like 'Brook: The <Insert Name Here>' just above where it lists the kind of stone. Streams and Rivers actually show up on the Region Map (the middle one), but Brooks can be in any region tile, giving you more leeway.
3rd, I'd recommend looking in Mountain tiles that border Forest tiles on the region map. There is almost always some spillover between region tiles. When you find a tile thats a mountain next to a Forest of some kind (Jungle/Swamp/Temperate Forest, doesnt matter), you can move around with umhk to select the proper spot - center it where theres some mountain and some forest in the local tab on the left. Mountains rarely ever have aquifers, and many of them do have brooks.