Ranchslider repair and maintenance

Ranchslider not shutting properly so there is water leakage. I have been advised by my roofer that track and channels of the door needs clearing, check for drainage, remove old sealant from corner mitres and reseal them. And adjust rollers so it closes properly and seal up around the vent. Hope all this makes sense. I have a couple of windows too that would cleaning and sealing as they are also letting water seep in.