Example of Umbraco GridSettings using the Bootstrap3.cshtml with Umbraco v7.5.4+

Bootstrap3.cshtml

@inherits UmbracoViewPage<dynamic>
@using Umbraco.Web.Templates;
@using Newtonsoft.Json.Linq;
@using Our.Umbraco.GridSettings.Web;
@using Our.Umbraco.GridSettings.Services;
@using Our.Umbraco.GridSettings.Resolvers;
@{
    var attributesResolver = new GroupByPrefixTokenGridSettingsAttributesResolver("_");
    var attributesService = new GridSettingsAttributesService(attributesResolver);
}

@if (Model != null && Model.sections != null)
{
    var oneColumn = ((System.Collections.ICollection)Model.sections).Count == 1;

    <div class="umb-grid">
        @if (oneColumn)
        {
            foreach (var section in Model.sections)
            {
                <div class="grid-section">
                    @foreach (var row in section.rows)
                    {
                        @renderRow(row, true, attributesService);
                    }
                </div>
            }
        }
        else
        {
            <div class="container">
                <div class="row clearfix">
                    @foreach (var s in Model.sections)
                    {
                        <div class="grid-section">
                            <div class="col-md-@s.grid column">
                                @foreach (var row in s.rows)
                                {
                                    @renderRow(row, false, attributesService);
                                }
                            </div>
                        </div>
                    }
                </div>
            </div>
        }
    </div>
}

@helper renderRow(dynamic row, bool singleColumn, IGridSettingsAttributesService<JObject> attributesService)
{
    <div @Html.RenderGridSettingAttributes(row as JObject, attributesService)>
        @Umbraco.If(singleColumn, "<div class='container'>")
        <div class="row clearfix">
            @foreach (var area in row.areas)
            {
                <div class="col-md-@area.grid column">
                    <div @Html.RenderGridSettingAttributes(area as JObject, attributesService)>
                        @foreach (var control in area.controls)
                        {
                            if (control != null && control.editor != null && control.editor.view != null)
                            {
                                <text>@Html.Partial("grid/editors/base", (object)control)</text>
                            }
                        }
                    </div>
                </div>}
        </div>
        @Umbraco.If(singleColumn, "</div>")
    </div>
}