Sounds like you are in a tough situation. Like the other said, IA University is a great start. Making things pretty in Perspective is very satisfying. Not sure if you have CSS experience but it's very helpful.
This guide helped me get started on a nice navigation menu: Docked Views - Dynamic Size Change? - #6 by danieltalbot
He's got a lot of great stuff. I recommend learning to use CSS grid. Much easier to control where components on the views sit: https://www.youtube.com/watch?v=8ahd-HET2_o
As for your dropdown issue, hopefully the data you need is sitting in a database somewhere. Go to Gateway>Config>Database Connections:
Then in your designer go to Named Queries, select the database connection where the data lives, and create a select statement like this:
Then you can go to your dropdown component and create a Query binding on props.options like this and voila:
One more tip. In perspective there's a concept called Brittle Connections. When you first start out putting compnents down in a view you'll be tempted to make direct connections between the components. The issue is that the connection is just a string, and the path depends entirely on the position of the component in the view(how far it's nested inside containers, container names etc). The better approach is to make custom properties on the view itself, and make connections from component A to view.custom.someProperty. Then component B can reference view.custom.someProperty. Now it doesn't matter where the components get moved to, the connection is stable.
Lots to learn, but you got this.