first thing first, the problem is that there are plenty of tsudanuma stations. the below description is for JR Tsudanuma station.
ok, take the Keisei Skyliner (京成スカイライナー）to Keisei Funabashi sta (京成船橋).
From there u walk to the JR Funabashi sta, u can't miss it, it's a 1-2 min walk and the route is well marked. From Funabashi sta u take the JR Soubu-line (総武線） towards Chiba (千葉） to Tsudanuma (津田沼）. the whole trip is about 50 min
the fee is (720+500)+150 = 1,370 yen
homepage for the skyliner can be found here:
link
u can also take the more "normal" special express, tokkyu (特急）, same line and same platform i think, from the airport and u don't have to pay the above 500 yen which is a special express fee. it's the same route. this will take u about an hour.
Come to think of it, there might be buses going to Funabashi sta. Also keep in mind that there r three stations with the name Funabashi in them.