The center of your mesh is at 0,0,0 in whatever 3d modeling program you’re using so your hips are at 0,0,0 when it should be your feet that are at 0,0,0. This means that whatever animation you play, it is centered from the hips and not the feet which is what is resulting in it looking like you’re floating. To fix this, edit the skeletal mesh in your 3d modeling program by moving it upward so the feet are at 0 on the height axis. As a result you’ll also have to edit the crouch animation so it has the correct height.