Custom CMS Page - Double Navigation bar

<%- if @topic_view.topic.tags.present? %>
<%= t 'js.tagging.tags' %>: <%- @topic_view.topic.tags.each do |t| %> <%= t %> <%- end %>
<% end %>

Silverstripe Version: 4.4.3

Question:
I am trying to set up a basic custom CMS admin. I want to be able to return custom content in place of the EditForm, but i am clearly not doing this correctly.

I need to have custom links to the next section of the admin, but every time i click one it does load, but with two navigation bars on the left unless i refresh the page manually.

I have tried to make sense of the AssetAdmin and the CampaignAdmin – but i can’t wrap my head around what changed.

Can someone give me an example of how i would render custom content in an admin, on a custom url handler?

basically a “show” function as well as an “index” function. ideally without having to write any new React.js since i have even less of an idea what to do with that.

I can provide code snippets if it helps, but since i have no idea what i’m doing they are probably useless.

EDIT:: if it helps for context – i want to be able to create a multiple step form, with some custom buttons to move on to the next step - but this is proving to be my problem.