How to make synthesis and fishing like in the Atelier games?

...Hello once again
Yes I think I'm actually just making an unofficial Atelier game
Anyways... How do you make synthesization?


And also fishing?


Thanks for reading!
And I hope that any one of you'll be able to enlighten me on the techniques ;w;

Explain how these features function?

You can use Yanfly's Item Synthesis with Item Core for... Synthesis.
For fishing, you'll probably have to event it.