If you have some programming experience then flutter would not be that difficult. Sometimes programmer with HTML or web programming background might find flutter is easy to start with.
If you directly want to start with flutter programming, then I would suggest you start with basic concepts like Row, Column, Container, Image and Text widget. Clear idea about these would definitely help you. You can really achieve some cool effects using them.
I would suggest to master Container. With these you can achieve very complex design.
After than you can slowly increase you skills with DecorationImage and AssetImage.
With these you can style your image.
And then you can also try to learn about PageView.builder or ListView.builder. With them you would be able to build scrollable pages or list.