You will need the Expert FGD to do some of these things. Get it here: http://www.superjer.com/learn_adv.php

1.) [...]how do i make it so i can see the wall from any distance....?
In Map->Map Properties set the max viewable distance to something higher. 11585 is just big enough for the biggest possible map.

2.) Whats the difference between Hollow Brushes and Solid?
Hollowing a brush breaks it into 6 new brushes, one for each side. It also groups them together. You can ungroup them with Ctrl+U.

3.) How can i make my character Spawn with a gun, like a scout?
Put a game_player_equip (point entity) in your map and check out its properties.

4.) How can i make it so when the character touches a certain brush, he dies?
Create a trigger_hurt. Just make a brush, put the AAATRIGGER texture on it, press Ctrl+T and choose trigger_hurt. Set the damage to something big like 300. Your trigger will be invisible in game, and the player has to enter its space to set it off.

..well how do u make it so when u land on a brush it takes you to another....
You need to use a trigger_teleport. Create it just like the trigger_hurt above and set it's target to something like 'bob'. Then create an info_teleport_destination (point entity) and give it the name 'bob'.