firstly take things slow, when you walk him be patient yet firm, when he's good give praise, when not correct him, the slap works for when he's being to excitable with the kids,,,has he got a place that he call his space away from the kids, like a crate or something . .
bring him to everywhere, he needs to be introduced to everything he'l meet in the rest of his life, buses, cars, trains, dogs, people, etc walk him little and often and always finish on a good note with him being good,
if you need any help pm me
lurcher lass xx