2.4 how do i get it

A little more context would help. What device did you have before? What did you replace it with? Are you broadcasting a single SSID? If so, 2.4 is probably there, you just aren't seeing individual SSIDs by frequency.

Many routers setup both 2.4 and 5.0 ghz with the same SSID. Your device , if it cannot use 5 ghz, will ONLY see the 2.4 and you can sign in with your SSID and WPA key.. If your device has both 2.4 and 5.0, it will select (steer) to the best one and login. 

Does this link help? Basically you want click the button to split bands.