I'm new to reading comics, so I have a few questions. I read X-men Messiah CompleX and loved it. Now I would like to continue reading X-men from that point, but I don't really know where to start. I guess I don't really know what comes next in the timeline. Does Messiah War happen right after Messiah Complex? I assume there are things happening at the same time in other X-men comics due to the fact that Messiah War happens mainly in the future. I don't know what I should read in order to understand what's going on fully and what order to read it in. After looking up a ton of stuff I feel like I'm on stable ground with the characters and plot. Any help would be greatly appreciated.

Not quite.  Messiah War does come later, but not immediately after Messiah CompleX.   
 
You have storylines like Manifest Destiny that immediately followed MC.  Then you had the first year's worth of stories in both Cable & X-Force which then led to Messiah War.  There was a gap of about 18 months between Messiah CompleX & Messiah War.

"Not quite.  Messiah War does come later, but not immediately after Messiah CompleX.    You have storylines like Manifest Destiny that immediately followed MC.  Then you had the first year's worth of stories in both Cable & X-Force which then led to Messiah War.  There was a gap of about 18 months between Messiah CompleX & Messiah War. "

" @Final Arrow: Fair point, but events in Cable & X-Force (especially) serve as background for Messiah War.  "