Please double-check that you are NOT deploying WEP as WEP is cracked for years now and your WEP key can be retrieved in a matter of minutes by an attacker.
If you really want to run with something that is less secure than an open SSID, there is a suggestion here that you should manually connect to the network using Windows 10.
Please do not deploy WEP. Also, your performance will be horrible as the AP will switch back to 54Mbps max (abg-wireless) as starting the 802.11n standard the use of WEP is prohibited by the standard.
Did I say already that you should not use WEP?
Do not use WEP.