Learn the basics of soldering two pieces of metal together.
How to solder zinc sheet metal.
What flux should be used.
Soldering is done with a zinc based alloy in either stick or powder form.
Feel free to ask me any questions you have in the comments.
I try to answer all questions in a ti.
Here is a helpful video giving you a quick rough how to on solder grinding fluxing zinc.
This how to video details the method of touch up and repair using zinc based solder.
Any advise of soldering copper sheets to stainless steel sheets.