Follow these steps

1. Open CMD (do not this window)
2. Type ipconfig /all and hit enter
3. Open Control Panel
4. Click Network and Internet
5. Click Network and Sharing Center
6. Click Change adapter settings
7. Double Click the adapter (should only be one)
8. Click Properties
9. Double Click Internet Protocol Version 4 (TCP/IPv4)
10. Click Use the following IP addresses
11. Enter the information from the CMD
12. Click Advanced in the bottom right corner
13. Under IP addresses, click add
14. Add the new IP address and the same Subnet Mask as before
15. Click Add
16. Close all windows but CMD.
17. Type ipconfig /all and hit enter
It should now have both IPs

For FiveM Servers

In the cfg file for each server, make sure to change 0.0.0.0 to the IP for that server