First of all, look out for your remote codes on the manual that comes with the remote itself. It could be written on a separate note, come within the box.
If you don't find it on manual then you can search here on our website. You will get live and working remotes here
The last option is to call the manufacturer to get the remote codes. Remove the battery latch, have your remote model ready and that remote manufacturer can tell you multiple & official working codes.