Netgear Wi-Fi extender EX6300v3

You gave us nothing to go off. Host router brand and model?
To get a hold of support. Click on "MyNetgear" at the top.
Register an account (or login) and then the device.
From there you can start the support process. Keep in mind that its only free for the first 90 days.
There's a support site with access to manuals, firmware, install guides, etc.
Go to https://www.netgear.com/support/
Type in your model number and from there it'll take you to the above.
Its a great resource to start with.

Netgear has set up a community forum specifically for the WiFi Extender products. Most of the people who watch that forum are more likely to have experience with WiFi Extender (EA and EAX Series) products. Might be more likely to find someone who has a solution if the question is posted there:
https://community.netgear.com/t5/WiFi-Range-Extenders-Nighthawk/bd-p/home-wifi-range-extenders

Please use this link to the main forum product list to review and choose where to make your posts. 
https://community.netgear.com/t5/NETGEAR-Forum/ct-p/en-netgear

Thank you.

What trouble are you having?

Details are key? 

What firmware is on it?

What router is it connecting to?

What method of setup are you using? 

Where does it error out? 

There's a support site with access to manuals, firmware, install guides, etc.
Go to https://www.netgear.com/support/
Type in your model number and from there it'll take you to the above.
Its a great resource to start with.

You can help people to help you by providing the information suggested in this forum's header:

Subject (Include model number and brief summary)
Model (Recommended - Helps the community give the best answers)
Body (Include additional detail including model version, firmware, OS and environment where relevant.)

They are there for a good reason.