I came over to the bass from the 6 string acoustic guitar where we played from fake chord sheet music.
I brought the fake chord sheet music over to the bass and belted out roots on the first beat. When I could do that I then added a 5 for R-5-R-5. When that flowed I added an 8 for R-5-8-5. That kept me busy for several years.
Here is what fake chord looks like.
http://tabs.ultimate-guitar.com/n/norah_jones/cold_cold_heart_crd.htm.
From here I cheat a little more. Songs in D. so I change the sheet music over to Nashville numbers. This will help.
http://www.guitar-chords.org.uk/chords-key-c.html
D- Em-F#m-G--A--Bm-C#m-D
R--2---3-----4--5--6----7-----8
So my A's are now 5's, the E's are now 2's and the D's are now R or roots.
Remember chords are listed as Roman numbers, I-ii-iii-IV-V-vi-vii. Upper case Roman numbers are major chords and lower case numbers are minor chords. The notes themselves (within those chords) are listed in Arabic numbers, 1-2-3-4-5-6-7 The 1 of often listed as the R or root. and then if you use Nashville numbers all chords are shown in Arabic numbers.
Why in the World would I do that? Take a look at the major scale box pattern I give below. That puts everything into generic patterns and makes my job a whole lot easing. Use as much of this as you like. I do suggest you copy and paste it some where you could find it later on.
As a warm up I would run my scales. Why? So my fingers could get used to the bass and my ears could recognize the good notes from the bad notes. I would recommend you spend time running your scales and you chord tone arpeggios (R-3-5-7-5-3-R) Get to the point that when you see a chord name your fingers already know what will be expected of them.
I used the major scale box, ran my scales and built simple bass lines. Fake chord calling for the Cmaj7 chord, just the C note on the first beat will get you started. Next chord showing as a Dm7 chord, here again the D note on the first beat --- and 3rd beat will work.
Here is the cheat sheet I grew up with.
Eat this monster one bite at a time. Enough to satisfy your hunger, but, not so much at one time that it makes you sick.
Good luck.