Need help from C/NH discbine gurus

I have a CIH Dcx131 which has the modular NH gearbox system. I have knife tips that are hitting each other and I realize that I have twisted connecting shafts, have bought the correct shafts but I'm a newbie when it comes to working on these things. Luckily the ones I need to replace are the end rod on either side , but does anyone have tips for doing this? TIA

Need help from C/NH discbine gurus