[header] How to restring a mandolin [title] Buy new strings. [step] You can buy a complete set of 8 strings or buy individuals if you are only wanting to replace specific strings. Different brand strings sound different, so if you like the sound of your current strings, buy the same exact strings. 
You should be able to find great mandolin strings at your local musical instrument store or from an online retailer. [substeps] Choose the strings that will be suit your purposes.