IP surveilliance Engineer Solution Provider

We want to hire a freelancer to make surveilliance solutions for custmers .Sometimes we make it according to customer's requirements ,most of time we need to make some solutions for them and you have to know how to create .You need to know security tecknology and you must know how to connect products in one solution ,for example ,an factory solution ,we have to know what device we have to use ,ip cameras ,DVRs ,NVRs ,Switches ,and how many of these device we we should use ,when we need to a POE switch in it and so on,then give a document to explain your solotion1 .If you are familiar in this area ,please contact me we will talk about it.