HETCOR is a 2D NMR experiment that identifies proton-carbon correlation. The carbon spectrum is on one axis (the x-axis here) and the proton spectrum is on the other axis (the y-axis here). The spectrum is a contour map. The peaks identify which proton and carbon peaks are correlated. Simply draw a line from a peak to the x-axis (the carbon peak) and the y-axis (the proton peak). These two peaks are "correlated", which under the conditions of a typical hetcor spectrum means that these are the protons directly attached to this carbon.
Notice that window was narrowed in this HETCOR spectrum to reduce data acquisition time. Look at the full spectrum. As a result, the proton peak at 9.75 and the carbon peak at 202.7 are folded in. The resulting hetcor peak is observed at H-0.7; C-38. The folded 1D proton and carbon spectra are shown in the original data from the instrument, but the 1D spectra plotted in Nuts and shown here were acquired using a wider spectral window so folded peaks are not observed (although the 2D hetcor peak is still present).