I want to render the content of my blocklist on the nav of my website, however, I get this error:

SiteBuilderBaseViewModel' does not contain a definition for 'CustomBlockList' and no accessible extension method 'CustomBlockList' accepting a first argument of type 'SiteBuilderBaseViewModel' could be found.

@inherits UmbracoViewPage<SiteBuilderBaseViewModel>
@using USNSiteBuilder.Core.Models
@using USNSiteBuilder.Core.Interfaces
@{
    Usnnavigation navigation = (Usnnavigation)Model.Navigation;

    if (navigation != null && navigation.CustomNav!= null && navigation.CustomNav.Any()) {

        int index = 1;

        foreach (var item in navigation.CustomNav) {
            <li><span><a href="#">item @($"{index}")</a></span></li>
            index++;
        }

        @Html.GetBlockListHtml(Model.CustomBlockList)
    }

}

I have followed the docs and created the Components folder under blocklist. The file inside is "CustomBlockList.cshtml":

@inherits Umbraco.Cms.Web.Common.Views.UmbracoViewPage<Umbraco.Cms.Core.Models.Blocks.BlockListItem>;
@using ContentModels = Umbraco.Cms.Web.Common.PublishedModels;
@{
    var content = (ContentModels.CustomBlockList)Model.Content;
}

<h1>@content.PageName</h1>

The final goal is to render what's inside the Block list and not the item @($"{index}"). Can anyone help?