Shows the simplest example of adding a modern web part to a SharePoint page.

addSPFxWebPart_Simple.cs

private static void addDefaultWebPartToPageSimple(ClientContext siteContext, string pageName)
{
    ClientSidePage page = new ClientSidePage(siteContext);
    ClientSideWebPart videoEmbedWp = page.InstantiateDefaultWebPart(DefaultClientSideWebParts.VideoEmbed);
    page.AddControl(videoEmbedWp);
    page.Save(pageName);
}