I am trying to gain weight but also have to lower my cholesterol levels. what is the best way to do this. ?

You need to gain: Healthy weight, as in lean muscle. The key for this is making sure you are eating healthy calories including lean proteins and healthy fats, while avoiding processed foods or simple sugars(sugars). Try to incorporate some form of resistance exercise too. Remember you can gain lean muscle and lose body fat(good from your cholesterol), but it takes time and effort.