Hi, I'm not sure what you mean by resizing the sprite. Sprites are always 8x16px in size in GB Studio 4.1.3 and earlier.
All assets associated with the beginner lessons are provided in the 'Beginner Lessons Resource Packs' folder that comes with the course. So you don't need to worry about creating or editing any assets. If you are following along with lessons 1 or 2, you only need to drag and drop the assets folder provided in those resource packs into your own project and follow the lesson PDF files.
There is a thorough instructional guide on how to use the course effectively. Read the (LBaP!) Course Introduction (v1.0) PDF document if you haven't already.
I would suggest joining my discord server and sharing your concerns there so I can help with your issue directly. If the lesson structure is not working for you or the follow-along beginner lessons don't make sense to you, I would love to know the specifics so that I may improve how accessible the course is.
Here is a link to my discord:
https://discord.com/invite/hv79RpMh87
Cheers.