self.gridView = [[NGVaryingGridView alloc] initWithFrame:self.view.bounds];
self.gridView.gridViewDelegate = self;
[self.view addSubview:self.gridView];

[self.gridView reloadData];

// You should return an Array which contains CGRects for every Cell you want to display inside the GridView
- (NSArray *)rectsForCellsInGridView:(NGVaryingGridView *)gridView {
    NSMutableArray *rectsArray = [NSMutableArray array];
    [array addObject:[NSValue valueWithCGRect:CGrectMake(...)]]

    // ...

    return rectsArray;
}

// return an UIView representing your Cell
- (UIView *)gridView:(NGVaryingGridView *)gridView viewForCellWithRect:(CGRect)rect index:(NSUInteger)index {
    YourUIViewSubclass *gridCell = (YourUIViewSubclass *)[gridView dequeueReusableCell] ? : [[YourUIViewSubclass alloc] initWithFrame:rect];
    gridCell.frame = rect;

    // setup gridCell

    return gridCell
}