How do I make a buffer with a specific pH?

use the henderson hasselbalch equation, to find the ratio of acetate to acid, whose pKa = 4.74

pH = pKa  +  log [A-] / [HA]

5.4 = 4.74  +  log [A-] / [HA]

log [A-] / [HA] = 0.655

do a 10^x of both sides

[A-] / [HA] = 4.53


this tells us that the amount of  acetate is 4.53 times as much as the acid

i.e 4.53 parts acetate @ 1 part acid,

(for a total of 5.53 parts)

 you wish to make up 1000 ml of  a 0.1M acetate buffer solution at pH 5.4

acetate : 4.53 / 5.53 (1000ml) = use 819 ml of  0.1 Molar sodium acetate

acid: 1.00 / 5.53 (1000ml ) = use 181 ml of o.1 Molar Acetic acid

your answer is to mix together:

819 ml of  0.1 Molar sodium acetate

with

181 ml of o.1 Molar Acetic acid