If you can, try setting up a few lessons. It's pretty easy to find someone via craigslist or something like that. You can go to craigslist and find your location, then go to Community section, then Musicians, then type in search box "Bass" title only, and hit search. You'll find teachers.
Some teachers will even give lessons over Skype. It's definitely worth taking a few lessons when you first start. Sure, you could checkout some basic bass lessons on youtube as well, but nothing beats being able to ask questions. You'll learn much faster and you'll develop good habits as opposed to bad ones. The key things that you should learn up front is:
- Tuning the instrument.
- How to hold the instrument while sitting.
- Proper left and right hand positioning.
- Fretting and plucking.
- The C Major scale.
- A simple song in C Major while tapping your foot to maintain a steady tempo.
That simple 30 minute lesson will be the most helpful lesson you'll ever have if you're serious about learning this instrument.
From there, do the homework that the teacher recommends (hopefully they make it fun) and setup a few more lessons. I cannot stress this more. Learning on your own will take much longer than sitting down with someone and playing together.
If for some reason you don't have the money for a lesson, then I'd suggest searching youtube for "beginner bass lessons". You might be able to find some quality lessons there. I've actually learned how to play the banjo pretty decently using youtube only.
Also be aware of the "I suck hump". Whenever you learn anything, you have to get over this hump. Emotionally, it's a bit difficult because for a while you're just going to think you suck and you'll never get better. But don't let the feeling fool you. The more you practice, the better you're getting, whether you see it or not. I remember when I first started, I had the "I suck" feeling for about 3 - 4 months and thought I'd never be able to do it, until a friend of mine said "hey, that's sounds pretty good!". And that's all it takes! It was an eye opener and it really pushed me over that hump. I kept practicing, and in 8 months or so I was already in a band playing basic rock!
If you really want to be a musician, perseverance is key for the first 6 months. Before you know it, all the things you struggled with on your first few lessons will be natural to you and you won't even have to think about it. Just like riding a bike. But from there, there's always something to learn and that's the beauty of being a musician in general.
Don't give up! The rewards are better than you can imagine!