Hello @Carine. We love having you here and I found reading your story amazing 
Thank you for sharing.
The software really is easy to use. If you can create a pattern on paper, then you can create a pattern with Seamly2D. The only difference is that you a sitting in front of a computer, instead of being bent over a table trying to reach the far corners of a piece of paper.
Just get to know the different tools in the software and the methods of creating curves nicely. The tools are easy to learn because there is always a small line of help in the bottom left corner of the screen, once you have selected a tool, to help you. And you can download a small manual in French here: User Manual - Seamly2D. There is also a manual for SeamlyMe here: SeamlyMe - Seamly2D but it is only in English.
For creating curves, this topic can help you: Curves with Formulas and here: Another "very mathematical" way of making curves!. If you right click on the page, you can choose to translate it into French.
Other than that, I’m sure you have noticed that we are a friendly bunch on the forum, who love to help where we can