If you want to use the color lookup table video effect on VideoPad, click the Video Effects button under the effects tab. Alternatively, you can also toggle the clip or sequence which you would like to apply the effect onto, then simply press the Alt+V shortcut key.

Once the Video Effects pop-up window is opened, it will display all the available video effects that you can apply on your selected clip/sequence. Simply scroll down and look for the Color Lookup Table under the All Color Effects category. (Note that you can bookmark effects simply by right-clicking them)

After the effect is selected, upload your LUT or Look Up Table file by clicking on the ellipsis (…) button under the Color Lookup Table effect tab. Once that is done, you may continue customizing aspects of your Color Lookup Table effect such as strength and parameters.