I hope you guys accept this cuz I'm really only trying to help, 
and it took me like 2 hours to type all this.

Beginners session.
Note! I put this here so that beginner bass players can learn 
a quick switch and play fast riffs and solos much easier.

Ok! Lets get started, The most important thing you need to know 
are the chords.
They are starting from highest to lowest, G, thats the tiny one, 
D, A, and E. Got that? Good.
You'll need to remeber these always as any tab made by anyone 
with common sense will have these chords on every bar.

Second you need to pick yourself a playing style.
Try a Bunch of different playing styles right now.
NOTE! Try not to use just one finger, if it feels easy, it will 
get increasingly hard to play fast song with only one finger.
I suggest my style, to always play the E with your thumb, the A 
with your index finger, and the 2 chords below with your middle 
finger.

Third, Well of course you need to learn how to play something. 
Just start Jamming some notes in, and try to play something slow 
with big notes.

Now, sliding, is a very important little trick, we'll practice 
this now.
Play According to the picture below.

G:———————————
D:———5—7—————
A:———————————
E:———————————
Play a 5 and right after playing it slide your finger across the 
string to the seven, and play that.
NOTE! The numbers btw... The higher the number the higher the sound.
Also the higher the number the lower the string is on your bass, 
therefore, after playing the 5 you slide DOWN to the 7, not up 
because that'll take you to a 3.

If this seems a little bit hard keep trying sliding with different 
notes, and playing riffs.
It'll come to you naturally.

Now lets try the... well I dont really know what this is called, 
but oh well.
Play as instructed in the picture.

G:———————————
D:———5/7—————
A:———————————
E:———————————
NOTE! You dont neccessarily have to use these notes. 
This is simple really, Play the 5 or whatever you choose to play, 
(Play the note hard so it stays for a long time.)
Right after playing the five put your next finger on the 7 but 
do not play it, Its a nifty trick, its like playing 2 notes with 
only one press.
IMPORTANT! Make sure once you play the 5 you do not lift your finger 
until you get to the 7.

Now lets try a double slide.
Play as instructed in the picture.

G:———————————
D:———5/7/5———
A:———————————
E:———————————

Ok, this is just like the exercise before except after you put 
your next finger on the seven lift it right back.

Now Lets try a short riff. I made this one myself, it should include 
everything youve learned so far.
We'll use 2 chords this time, and if you play it right it should 
have sort of a funky feel to it.

G:———————————3/5———————————3/5/3———————————3/5————————————3—5——————
D:———3——3——3——————3——3——3—————————3——3——3————————3——3——3———————————
A:—————————————————————————————————————————————————————————————————
E:—————————————————————————————————————————————————————————————————

If you cant get this on your first try keep trying until you get 
it right, this is an important lesson, because you will NEVER 
learn a song on your first try.
Not EVER! I guarantee it. So instead of never ever learning to 
play bass in your life I suggest you try this until you get it 100 
percent right.
It shouldn't take too long considering this is a very basic riff.

Next step.
Now we're gonna bring up the speed a bit. k? Good.
Whoa, Whoa not too much, your trying to learn bass not become 
the next Flea.
Ok here's your next riff. We're gonna use 2 chords again.

G:——————————————————————————————————————0—0—3—3—3—3—3—3———3—————————
D:——0—0—5—5—5—5—5—5—3—3—3—1—1—1—1—1—1—1—————————————————3———3—5—————
A:——————————————————————————————————————————————————————————————————
E:——————————————————————————————————————————————————————————————————

IMPORTANT! I made sure this riff sounds good at just about any 
given speed so try it slowly first, and slowly begin increasing 
your playing speed.
Just remember this is made to have every note playing at the same 
rate, and every break should be just as long, of course if you 
play it right there will be no breaks.

Ok You can now play basic slow and fast riffs.
As the last step begin jammin' Right NOW! Just start playing 
random notes until you find a couple good ones.
Then convert them. Pick up speed perhaps, Maybe add some more 
slides, whatever it is you want to add in there.

Once you have learned how to play decently enough, try to play 
an actual simple song.
I think I'll Include one of my own here

This is a wonderful sounding song, it's Red Hot Chili Peppers, 
This Is The Place! Tabbed by myself.
I love this song. Period.
Here it is.
ENJOY! Shouldn't be too hard to learn.

G:———————5—5—————————————5—5—————————————————————————5—5—————
D:—7—7—7—————5—5—5—3—3—3—————7—7—7—0—0—0—7—7—7—3—3—3—————5———
A:———————————————————————————————————————————————————————————
E:———————————————————————————————————————————————————————————

G:———————5—5—————————————5—5—————————————————————————5—5—————
D:—7—7—7—————5—5—5—3—3—3—————7—7—7—0—0—0—7—7—7—3—3—3—————5———
A:———————————————————————————————————————————————————————————
E:———————————————————————————————————————————————————————————

Ending
G:——————2—————————————————————————————
D:————————————————————————————————————
A:—0—0————————————————————————————————
E:————————————————————————————————————


Good luck becoming a pro. I hope this guide helps, cuz in that 
case you were just taught how to play base ny a 14 year old!! :)