Well, the command apropos is good for finding commands. Say you want to know how much memory you have on your HD but don't know which command to use, then you type 'apropos memory' and you get a list with all the regula commands dealing with memory. It allso give you a short explination of what the command do, so when you find that the command df seem to be what you are looking for you just look in the manual ('man df') and find out you just type df -h to get the avalible and used space in human readable form.
This is a good place to start for anything. First search the command with apropos, then read about it using man.
As for finding programs and directories you can either use the command locate:
The locate command use a database which you need to update... all of this is in the manual, so just do man locate and it will tell you how to update the database.
Or you could use find:
find / -name apache -print
The / tells find to search from / and all directories below that... in other words, the whole drive which might be unncessesary if you have an idea where the thing might be, you could just aswell typed find /etc -name apache -print to search the /etc directory.
Allso, here you have a link where is a good place to start if you are new to BSD. It explains how you get the basic stuff up and working:
daemonnews "new to BSD" area