hey new and sorry

i know there is almost defenatly a tutorial but im not sure exactly what it is im asking, like to search the technical term for it & i cant find it, so i just made my 1st model on blender a low-ish polly base man for a game im making i used the mirror feature, butt its kind of like a fake mirror, and i want it to have joined seams, like because i need to animate full models once there completed, also… i dont know how to like align the vertexes like so if i properly mirror it, i dont want it to be joined at the furthest out vertex, if that makes sence… like i want from the top of his head to his crouch to be aligned and also i just want the middle to have the center vertexes in the right place, sorry for the poor wording

I assume you are using the mirror modifier.
Select clipping in the settings to prevent the vertices crossing the centre line (the centre line is based on the objects origin point). To make the mirror real just apply the modifier.
Documentation: http://wiki.blender.org/index.php/Doc:Manual/Modifiers/Mesh/Mirror