right click over the model and select isoparm.
Next, drag an existing isoparm into your new position ( you should see a dotted line where the new isoparm is going to be created.
If you need more than one new isoparm then hold the shift key down and drag a new isoparm (the same as you have just done)

When you have all the extra ones you need, then select
Edit nurbs - insert isoparm