Need to repair your Nintendo Switch? iFixit is a great one-stop shop for guides, videos, parts and tools. Here is their section on the Switch:

https://www.ifixit.com/Device/Nintendo_Switch

Each repair guide also has links to buy the parts from them (if you choose, you can certainly also find them elsewhere but make sure you check the reputation of where you're buying from) as well as any necessary tools if you're needing those too.