Setting up wifi range extender

Yesterday I purchased a AC750 Wifi range extender model ex3110. I am not able to set it up with wps because my router does not have that as an option. The other way to do it is by connecting to the extender and going on a web page to connect it through the website provided, but when I try to pull up that page after connecting to the extender it says the web page cannot load because I am not connected to the server. The only way I can pull up the website is when I disconnect from the extender, but then I cannot set it up. I watched a video online and it seems like I am doing everything right but it won’t seem to work. Please let me know if there is something I am missing or any other advice. Thanks