With respect I think that you are mixing too many ideas at once.
As you appear comfortable with the Windows OS perhaps you might connect to your AP and configure it by opening a browser and entering the admin section. You can configure WEP there.
Once you are satisfied that you can access the system then move to using Linux.
In Linux you will need to ensure that your card is listed in response to the command ifconfig and furthermore you can then utilise iwconfig to enter your parameters for connection. You will need to use a wpa_supplicant as you move to WPA variants.
Kwifimanager is buggy I recall though it may have been updated.
Finally you will need to manually call for the issue of an IP address once associated using dhcpcd interfacedevice
You might then try to connect to the internet assuming that your AP has been appropriately connected.
Finally, do progress to searching the forum here for details and advice for your card.