Since you ask for soldering practice and not understanding electronics. My advice would be cheap, find some electronic device that no longer works DVD player, Radio, Battery charger, phone charger, Remote control, something with smd components. Learn how to unsolder the parts first, then try soldering them back on, something like soldering two wires together will gain you some practice. It’s not rocket science it just takes practice and experimenting and the right tools to work with will help tremendously. Save your money for better fluxes and solder or a heat controlled soldering iron or hot air station. My 2 Cents 