The DG Bass Chord Patterns Android application is very easy to use.
The screen is divided into 4 regions, as shown in the following figure:
There are four regions: 3 button grids, and one central graphics frame:
When you are operating the application, all you have to do is to choose one button from each of these button grids.
Immediately after, the chosen chord is displayed on the central frame, the yellow area on the figure shown above.
The central frame displays the chosen bass chord pattern graphically, and also by name (on the right).
The graphical image displays only four frets of the bass, which is sufficient to display all fingering positions of any chord.
When the chord pattern is close to the head, or nut of the instrument, it shows a double vertical line, as in the figure above.
When the chord pattern is on higher frets, it shows a number on top of the first fret; all subsequent fret and number positions are relative to this fret number. This is the standard way of representing bass chord patterns.
When you tap on the fretboard, it switches between displaying the notes of the chord pattern, or the intervals.
The intervals are particularly important for a bass player, because on any chord, the root ("R") and the fifth ("p5") are usually the important notes played by a bassist.
Pressing the 1, 5, or 9 buttons will take you straight to the pattern as seen on those frets, respectively;
alternatively, press the ">>" or "<<" buttons to see the pattern starting from different frets (such as 2, 3, 4, 6, 7, etc).
The strings are positioned from the viewpoint of a bass player, with the instrument on its lap, (bass head on the left, body on the right) looking down at the fretboard, with first string on top of the image (bottom of the bass, further away from you), and fourth string at the bottom of the image (top of the bass, closer to you). Other books and charts represent the chords in different orientation, but we find this way very intuitive.
On the left of the nut, white circles represent the strings that are played open ("o") on that particular chord pattern.
On the example shown above, there is an "o" on the 4th (E) string, because it is part of an E major chord.
The circles in pink color represent the possible finger positions, showing the notes of the chord pattern, as they are placed on the fretboard.
If you are a newbie, we suggest you learn all the major (M) and minor (m) chords, and 7ths first, followed by the 6ths, dim, and aug. This covers 80% of the music available, and then gradually, you may learn the most sophisticated chords 9ths, sus4, etc, as you need them.