There are two teak strips the first being the forward handle. The second not seen except for the screws seen on the underneath of the slider holds the other piece on top acting as the slider stop. It runs the width of the slider. The caulking has to be replaced from side to side. You Weill see screws on top of the slideron each side take them out on one side. Do this with another person supporting the slider or you will get hurt by yourself only.
The part rgranger mentions is a companionway cover I had a mfg make them to attach over the top of the slider hatch. You will need to put something underneath that cover so water will not pull. If the boat has a companion way cover, order the slider cover w/o the snaps installed as you will want to fit the snaps yourself so not to have a second row of snaps on top.