Namespace="BotDetect.Web.UI" in aspx.vb file?

Hello
On this page here: https://captcha.com/doc/aspnet/asp.net-webforms-captcha-quickstart.html
where it says
2. Show a Captcha Challenge on the Form
On the ASP.NET form you want to protect against bots, add:
<%@ Register Assembly="BotDetect" Namespace="BotDetect.Web.UI" TagPrefix="BotDetect" %> I take it they mean the aspx file and not the aspx.vb file on account of the <% %> that appears at the top of an aspx file and not an aspx.vb file? On the other hand, wouldn't
Namespace="BotDetect.Web.UI" normally be placed in the aspx.vb file?
At the moment, my code looks like this only:
ASPX:
<!-- NuGet Captcha --> <BotDetect:Captcha ID="SampleCaptcha& ...