how to make this cylinder model with holes Im just new to blender just few 2months learning. A file attached i want to make the holes on the cylinder. The holes on the cylinder and its just twisted and alternative. Any idea I want to know i have to make plan and twist it or i have make the cylinder and cut the hole. Just confused both not working

EDIT

thanks for reply. I have made the cylinder in other manner. I have taken the plan and subdivide 28 times. Then i got group of squares. i have made the square select and the checker select deleted the square and added sub modifier and bend 360 but the problem is that the at the edge of the plan y it has made the gap of one hole and not looks continuous. And plz tell me how to attach the blender file so that u know where im wrong. Mean time image attach
Create a cylynder, and subdivide it the number of times right to have one hole in every column; then add (CTRL R) some loop cut just to have square faces; select every face corresponding with the holes (you can try the checker deselect function) and delete them (X, Enter).

Then add a subsurf modifier, and you'll have your holes.

You can improve the mesh with a solidify modifier and playing with edge creases.

A lot of functions you use in edit mode have their parameters regulation in the "T" panel, left-down the 3D Window, as shown in the picture.