How is memory address applied to address pins in RAM chips
Actually those 4 dots mean repeat. This means there are $2^{20} = 0x0FFFFF = 1,048,576$ memory cells, each with a line from the decoder. A few too many to draw them all.

Each of the lines from the decoder to a cell is an enable line. If not enabled the memory cell will do nothing (and have any output lines set to the data bus high impedance). If enabled the memory cell will read and write as you would expect.