There are five types of H here, a CH unit, a CH₂ unit, two different CH₃ units, and the -OH unit, so we see five sets of peaks.
The most deshielded group (higher d / ppm, 3.71 ppm) is the C2 CH unit with the electronegative oxygen atom attached. It has 5 H neighbours (1 x CH₂ + 1 x CH₃), so the n+1 rule means we see the 6 lines of a sextet.
The CH₂ unit has 4 H neighbours (1 x CH + 1 x CH₃), so the n+1 rule means that we see the 5 lines of a quintet.
The C1 CH₃ unit is closer to the electronegative O atom and so is slightly more deshielded. It has 1 H neighbour, so the n+1 rule means we see the 2 lines of a doublet.
The C4 CH₃ unit is furthest from the electronegative O atom and is the most shielded peak. It has 2 H neighbour, so the n+1 rule means we see the 3 lines of a triplet.
Hydroxyl protons (-OH) typically do not couple (due to exchange properties) so it appears here as a singlet.  They are also quite variable in their location (0.5-5 ppm). In this case it appears at about 2.4 ppm.
Integrals are in a  1:1:2:3:3 ratio.