In this video

Position the tip of the caulk gun in the corner of the joint. Apply steady, consistent pressure to the trigger while moving the gun smoothly along the seam. The goal is to lay down a continuous and uniform bead of caulk that adequately fills the gap. Avoid applying too much caulk, as this will result in a messy and difficult smoothing process. If you notice a spot is too thin, it is easier to add a little more caulk later than to clean up an excessive amount.