SDS and STD documentation

Hi i have a system that will be developed soon and i want the documentation for it to be done, the documentation is already started but now need someone to correct the mistakes and finish it, the person please needs to be good in use cases design, sequence diagrams and all the other stuff, because we are not software experts and we need someone who can take decisions, if you accept then please be open to go in a meeting or a call here for further explanation