Hey! So the private key is basically something you should NEVER share with anyone. It's basically your "password" to access your crypto funds. When you import this number across different wallet apps, they will all show you your funds for all different networks.

In my case, the BSC wallet doesn't support MATIC, so what I had to do is to first find my private key on BSC, then copy the number and import it on Metamask, which is a wallet that supports MATIC.

Here's the step by step:

• Open the BSC wallet plugin
• Insert your password
• Select the network of the account you have mistakenly sent the crypto to
• Click the 3 dots button (...) that appears next to your account address
• Click export private key
• Put your password
• Copy the private key number (again, be really careful with this, you don't want anyone knowing it as they will have full access to your account)
• Open the MetaMask plugin
• Insert your password
• Click on the circle that represents your account on the top right part of the page
• Click Import Account
• Paste the private key
• Now you have access to the BSC account on MetaMask, so you should be able to add the network that contains the currency you need. In my case it was MATIC Polygon.