The top line represent the 1st sting that is tuned to G The line below the G note is tuned to D The line below the D note is tuned to A Final line( bottom line of the 4 lines) is tuned to E
This tab will help us to find all the 12 notes on the E string.
The metal strips on the Bass are know as frets. Try and find the 1st fret (closet to the nut i.e. all the 4 string will run on top of the NUT( they like 4 slots) now try any finger to begin with and place it behind the fret( finger | (|=fret) (and press it down and the with right hand hit that 4th string and clear sound should happen and don`t worry it it buzzes as it does take some time to practice a clean sound)
I may try a video for this to help you along with texts. Tab below with all the 12 frets. As a bonus I have left each open string (A D G) so that we can see that that open string can be found on the E sting.
Final part This tabs is help you find each note on all 4 string. We only play one note not all 4 as you have might have guessed at that would be impossible.
Like for example we want to play an E note
From the tab we can see that E string is Open A string 7th fret D string 2nd fret G string 9th fret
Hence in your own time you can find any note on any string
Again if needed we could do a video to demonstrate this idea.