Use of Custom UI with Forge UI Kit on a Dashboard Gadget

I’m ussing Forge to create my first plugin for Jira and need to create a Dashboard Gadget for reports, I’m using UI Kit for my admin page and globlal page but now I need to use a custom UI for reports inside a dashbord gadget,.
I used the documentation and created a Hello World dashboard gadget but now I can’t change it to use a custom ui.
Any help on how to achieve this?