pls could someone help me set upa a wireless wan...like LTE modem connected to my tplink router from wireless wan...then tplinks's vpn ..distributed via lan

Is this what you are looking for:

Combined with those for more information (for phone, but could be helpfull):

I successfully did an USB-tethering as a WAN network with a Samsung phone but I don't have any experience with LTE modems. USB-tethering provides better performances than WiFi-tethering. Hope this will help you until someone step in to fill the blanks.

what if my tplink dont have a usb....is there a tuts to connect a wan to wireless wan---like i have an LTE modem with wifi then connect my tplink thourgh wifi...is it possible

Using another WiFi network for your ISP is called routed client. The other network can be a portable LTE hotspot, smartphone in hotspot mode, or a fixed location like a cafe or hotel. The setup is the same. Basically you create a wifi client interface and attach it to the WAN network. Make sure the WAN network is not a bridge and nothing else is attached to it. For typical instructions, search for "routed client".

thanks !!!! god bless