Probably the best source is in one of the moderator's sig's:
has the Linux: RUTE Users Tutorial and Exposition
listed, and that is probably going to give you the most info that is relavent to nearly any distro.
I'll give you quick answers though, and then you can research them in that manual to understand them better:
1. 1 what an IP address, subnet and default gateway are for and how to configure them?
To connect a computer onto a network (being internet, intranet, LAN, whatever term is being used). You configure them with ifconfig and route.
2. 2 How to use/navigate around Linux using only the console?
Well, this is kind of an open ended question. You use a shell (usually bash) and then short commands to move around, such as cd, cd .., cd /path. You also list contents of directories with ls. You show your present directory with pwd. Using
the console to me would simply mean typing these commands into it. You also use the console to compile, to run terminal based applications (mpg123), compile a kernel...
3. How to mount a partition using only the console?
An example for your first partition on your primary IDE drive:
mount /dev/hda1 /mnt/hda1
You have to have the mount point /mnt/hda1 created first. You also have to have a filesystem on the device. Using fdisk you create a partition, then using mkfs.DESIREDFS, you create the filesystem. So, for ext3:
mke2fs -j /dev/hda1
Would create an ext3 partition on /dev/hda1. Then, you pass that to mount with the -t option if it doesn't figure it out on it's own:
mount -t ext3 /dev/hda1 /mnt/hda1