creating vertices in 2d

Hi I am having a bit of trouble with this I can not figure out how to create new vertices and make them not move along for example the x axis. I have very little experience with 3d modeling so I do apologize if I am asking a stupid question. I am currently modifying a weapon mesh for fallout an I wanted to add some small details to it.

I want to thank anyone who want to give me any advice in advance.

No question is stupid when you are new. I would head over to blender cookie and watch Jonathon model everything you can, it will come.

What you are looking for is orthographic projection. Just press 5 on your numpad to toggle between ortho and perspective, then use the numpad keys 1 3 and 7 to access your individual views front, side, top. To get to the opposite sides, CTRL 1 3 7.

A lot of modeling is view dependent, your movements are determined by where you are looking at it, and where the 3d cursor is. Proper use of the 3d cursor can accomplish almost any task.