Safety does not work after replacing trigger

[w123driver]

I installed Timney trigger on Mark X,Yugo Mauser). The bolt cycles and cocks fine, but the side safety has become dysfunctional. The gun would fire when safety is on, although the bolt wont open,will open after safety slides off). The trigger manual says something about building up at one point, or removal metal at another point. The diagram it refers to does not make a sense to me. Perhaps anyone could explain? Thank you!