WAP Configure

[#1]

I have an ethernet port in my loft where wifi is not so great. I'm looking to create a WAP using a 

TP Link WA801ND 

Maybe I've looked at too many tutorials on how to best achieve this, but now find myself confused.

I want simply to improve wifi in my loft so it's similar to what I get closer to my Plusnet Hup One router  on the ground floor. 

I don't want a new network, just to extend my existing plusnet wifi reach to the loft.

Should I be setting TP Link as a WAP or Client mode? I've seen configs for both.

Can it be that house wandering users will automatically change to the strongest signal source depending where they are in the property?

Bit lost with all the various settings and options etc.

I imagine this is quite straight forward to somebody with networking knowledge, but that's not my strong point.

Any help and /or advice gratefully appreciated.

Dave

[#2]

@dsmail 

If you're connecting it to an Ethernet cable from your router them it has to be set as a WAP. If you are using it as a wireless extender,then it's the extender mode.

It's worth trying but you might have problems with some devices if you use the same SSID as your router.

[#3]

Thanks. This is helpful.