How can I make a dotted line or something else like that to indicate the number of bars I want a ritardando or other things of that nature to last? I should note that this is for a live performer.
There are several ways, but probably the easiest is to use the "LineSpan.nw" object.
https://forum.noteworthycomposer.com/?topic=9467.0
Requires NWC 2.75a - check your current version with |Help|Access.noteworthycomposer.com| if you are not current you can download the update.