You don't weld silver bracelets, you solder them.
To solder a silver bracelet you need a gas torch (not a soldering iron), silver solder and the right tools to make the edges smooth/clean and a perfect fit.
First you prepare the edges, which will need to fit exactly together and to be super-clean. Then you prop up the bracelet with the join together, then you apply either silver solder slivers (called paillons) or paste. Next you heat up the area until the silver solder flows and melts. Then it's a case of cleaning off the area using what's called pickle, then filing it down, polishing and finishing (can be done in a tumbler)
It's not straight forward, you need equipment and skill/practice.
Hope that helps to understand the outline process.