Ditto for the lessons. I am a euphonium player (otherwise known as a tenor tuba

). It will only help your bass playing. Some suggestions:
Of course, get a teacher.
Find an Arban's method. There's one out for tuba now, but I think it's mostly for CC tuba, and from what I understand, you have a BBb. It's also like 50 USD. You can buy the trombone version and read it down an octave. The baritone fingerings noted in this edition are the same for BBb tuba, just an octave higher. And by the way, tuba reads "at pitch" rather than an octave higher than it sounds, like the bass does. The
trombone method (the old one, edited by Charles Randall and Simone Mantia) is less than half the cost of the "new and improved" edited copies. The way I see it, you will never perform these on stage, so who the hell cares if you're playing the right notes or not?
Have the Arban's method (of which I can give you PLENTY of useful exercises and how to play them), and get a beginning method as well, such as "Best in Class" or "Standard of Excellence."
Until then, play long tones on your Bb note. It will improve your tone until you can get a book and learn to play other notes. Then when you learn those notes, play long tones on them. Long tones on lower notes helps the tone of the whole range of the horn.
Listen to the Dirty Dozen Brass Band and the Youngblood Brass Band, to get an idea on how you can use the tuba in modern situations.
Nick