I need help with potty training pitbull!!!PLEASE?

we recently adopted a pitbull frum someone,Herez tha situation,previous owners say she showed up at thier doorstep,an iz a sweetheart,dont know here age exactly,prolly a lil over a year old,she iz not agressive,an we think a man may have abused her,because she doesnt seem 2 trust men,she iz very friendly ,but when someone is new 2 her she will get all excited an go up 2 em,sit down,an look up at ya till ya show her sum attention,when ya go to rub her head she lays on her back or crouches down and pees,other than that she listens,when she needs 2 go out,she will come lay her head on tha bed or go stand by the door,till ya take her out,also good with kids,jus someone she iz new 2.ANY ADVICE OR SUGGESTIONS WOULD BE GREATLY APPRECIATED!!THANKX!