3d Models Skinned

[Watspoon]

Hey Guys! I'm not exactly the best at making custom models so I need a bit of help here. When I open OpenBRF and I press on one of my custom models (which is a cav uniform) their are a number of checkboxes in the area right of the list of models. The skinned checkbox isn't checked off so I was just wondering how one might go about checking it! Any help is much appreciated