First step, enter the wiki page.  (Shadow Force Wiki)  The wiki has some very useful basic editing features represented by icons

to start with we will make changes to one of the NPC.

Click on the name of the item you want to view.  (For this demo we will use Oksana.)
To make changes to the text, click edit.
Then type the info, character back story and other pertinent info.
To make links to other wiki entries in the Shadow Force wiki, place square brackets around the item.  example, if I wanted to say that Oksana was a friend of General Fastrax and that she is on the DarkFire.  I would do it like this.

[[Oksana]] was hand picked by General [[Fastrax]] to join the [[DarkFire]] team...

If you spell the names correct the wiki will link to those other wiki pages.  You can also link to other wiki pages and use a different title.  Such as if I wanted to use the nickname of Fastrax as Fasty.

[[Oksana]] was hand picked by [[Fastrax|Fasty]] to join the [[DarkFire]] team...

the "pike" key is used between the to items.  Usually found above the enter key.
to add a link back to the main wiki page you can add it like this

[[WikiHomePage]]

I did this for many pages until I figured out that I could make it look nicer by using the "pike".  So I now do it like this...

[[WikiHomePage|home]]

Its very important when entering a link that is exactly the same as the page you are trying to link to.  For example if I was trying to link to the [[DarkFire]] but not [[Dark Fire]]  the second one will link you to a new page.
If you are unsure what the already existing page is called it is always on the top of the page when you arrive at it.