Nursing Care Plan Help

Hey guys! So I'm a 1st year nursing student & my class just recently started to do Care Plans. Unfortunately, I'm just not understanding how to do it. My professor just basically touched base on it & by the end of class, EVERYONE in class was equally confused. I understand the Nursing Assessment but I can't seem to apply this knowledge to make an accurate care plan. Please help! I have to at least make 4 Nursing Diagnoses as well as complete the care plan but I'm not sure if I'm doing this right. So far I have "Constipation R/T poor eating habits a.e.b. anorexia." Am on the right track?

I.J. is a 78-year-old woman admitted to the hospital with a Dx of heart failure. I.J. lives by herself in her own home. Her Sx are severe fatigue, poor memory, & concentration. Her hair looks dull; she is pale & has anorexia & constipation. She is also very sensitive to the cold. She has 2+ edema in her feet & legs. Her heart sounds are distant. Her lung sounds are diminished but clear. Her BP is 110/60, heart rate 56, respiratory rate of 20. She is 5'3" & weighs 142 lbs. Her daughter states that Mrs. I.J. weighed 157 lbs at the physician's office 6 months ago & that she has eaten very little for several weeks. Mrs. I.J. smoked 20 years ago. Past Hx included CVS 10 years ago with no deficits noted.

In the hospital:

Code status - limited

Diet - Cardiac

Activity - OOB to chair 3x / day, BRP

Medications:

Lasix 40mg PO daily

K-Dur 20 mEq PO daily

Aricept 5 mg PO HS

Lopressor/HTC 50/25 mg PO daily

Hydromorphone hydrochloride 1 mg IV q 4 hours PRN

Coumadin 2 mg PO daily

Megace 4 mg PO daily

Lab results:

WBC - 9.8

RBC - 3.57

Hgb - 10.0

Hct - 29

Platelets - 127

Potassium - 3.5

Sodium - 135

INR - 2.5