I need to use WRT 300n and WLC 2504 in Cisco packet tracer in the same topology. WRT 300n connected to WLC 2504. and I need to ping other devices from remote device. I couldn't find any examples where these two are used together. Would you help me with this topic
You say this is in Packet Tracer... I know the WRT300n is Cisco-Linksys, but I don't think it would be available in Packet Tracer. WLC 2504 is also end-of-life, so I don't expect to see it in PT, either.
At any rate, it's normal to keep vendors lined up: Cisco with Cisco, not Cisco with Linksys or Cisco with Meraki. Even though they share the same parent company, the product lines aren't designed to be interoperable.