Well done on the first project!
I can't answer the image importing questions but, for the other things...
I also came to Decker without any scripting knowledge and also found the documentation hard to understand at first.
But because so many things in Decker are possible without knowing Lil (making cards, connecting them with buttons, etc) I think it works quite well to learn Lil gradually based on what you're interested in doing -- seeing a working example of something usually helps me understand enough to use a similar script in my own decks. So, yes! I definitely think you can make more and more advanced decks! But what steps to take or what examples to look at will depend on what you're interested in making.
Everything in the examples folder is unlocked (I think...) so you can always go into widget mode and see how any of the examples are made to see a variety of small scripts in action.
The link in your deck should work if the text field was 'Locked', with the Widget menu. As a side note... an unlocked text field can be re-written by your player. For your project I'd probably recommend locking your fields when you're finished. And it will fix your link.
For creating pacing on a card... to make a widget appear, you might want to use this:
widgetname.show:"visiblitymode"
For example... if you set up a card to have your widgets set to "none" (you can do this from the widget menu), and your first piece of text was in field1 you could use
field1.show:"solid"
in a script to make it appear solid, like it is now.
For making certain things happen with intervals you can use sleep[]. Sleep creates a pause, and a larger number inside the [] makes the 'sleep' last longer. An example of what that could look like is:
field1.show:"solid" sleep[50] field2.show:"solid" sleep[50] buttontonextcard.show:"solid"
If you make a test button on one of those cards that contains a script like this (with the correct names for your widgets... put everything between "on click do" and "end" inside the script) you could try out different timings and see if it gives the effect you want.
If it is, then me or someone else can give you some ideas/examples of how to make it autoplay.
I'm sure other people will have thoughts as well. 🙂 And welcome!