1. Right click on a state and pick either build new factory or view factories --> new factory.
For resources I think you can right click and pick expand resource or you can click the expand resource button on the right hand menu.
2. Do you have manpower? If not convert some pops to soildiers. Once you have manpower click on the military button which is next to the crown. Then click build new division.
3. Maybe you are about of DI? Or that country might be a satilite so you can't offer many offers to them.