posted 2 models
TL-WA901ND is a AP
TL - WR741ND is a Router
On which one you need help, the thomson st510v6 is a modem router, and WR741ND is a Router too, so for the WR741ND to work, set WR741ND ip on different su-net like 192.168. 0.254 or 192.168. 2.254 you will connect to the WAN conector the blue one.
And you post I tried to setup my tp link access point if thats what you want same instruccion of IPs and disable DHCP you will conect lan cable to any of the 4 outlets connectors the yellow ones, with this configutation

i did post for TL - WR741ND ... I didnt post for TL-WA901ND but i marked it as i didnt find my model of router.
and you know TL - WR741ND wireless N router
thomson i have is my main modem that have my home phone link pluged to and i take dsl cable from my thomson modem to this tp link wr741nd ..
my thomson is 192.168.1.254....
so my question was wt ip to choose for tp link router so it can work thru my thomson?
thank you

i have answered your question on post #2 gave you 2 configurations one for Router mode and and other for AP mode.
if you do not understand, let me know and I will elaborate my answer, or you can follow these FAQs
http://www.tp-link.com/en/article/?faqid=417
http://www.tp-link.com/en/article/?faqid=147
http://www.tp-link.com/en/article/?faqid=143
http://www.tp-link.com/en/article/?faqid=92
http://www.tp-link.com/en/article/?faqid=67
http://www.tp-link.com/en/article/?faqid=430