Welcome, Mary!
Where I work, the bed linen is changed at least twice a week, on shower days. (One shower is on days, other is on 3-11's). Of course, if the person has an 'accident'.....
As for meals, EVERYone is up for meals. Decreases the chance of choking incidents.
There should be an ADL available for each patient. Find out where they are kept, and look them over. Often, you CNA's are the ones who notice the little changes that indicate something's going on.
'Cat'