In the olden days patterns were hand drawn and almost every women knew how to sew. So if the pattern's lines didn't match they knew how to correct it themselves. So I thought I'll use this trouser pattern as an example for you to explain myself.
If you look at the back and front of this trouser pattern, you'll see the front is just straight lines and the back is flared. So you either need to straighten the back pattern or flare the front pattern.
In the next two videos I'll show you how to use your curves on this trouser pattern.