This really is quite a mouthful to ask in the title so i will explain just what im asking. Assuming im starting with a blank sleet and I want to make a low poly model and a high poly model how would i proceed? would i first make the high poly model and remove detail or vice versa? or do i do a different approach? also what are some rules i need to follow in order to make sure when i bake the high poly mesh on the low poly mesh at the very end it doesnt turn out all messed up. thanks for any answers 
As the title says how do i do it? assuming im starting on a blank slate and I want to make a person or perhaps a gun, would i make the high poly texture first and remove detail to make a low poly texture or would i start with a low poly texture then add lots of detail to make it high poly. Even more than that, are there certain parameters i need to stay within when making my high poly model in order for the whole thing to not look demented when i bake the high poly mesh onto the low poly one? Try and use simple terms or my brain might explode and thank you for any answers
What do You mean by “high poly texture” and “low poly texture”?
High poly / low poly stuff has to do with making a low poly model that “looks like” high poly model. Low poly model can be rendered faster, and can be made to move around in real time as in the games.
So, the trick is to make low poly model looks like high poly model. The “looks” of high poly model is transferred to low poly model with the use of UV mapping and “Baking”.
UV mapping of a low poly model requires you to unwrap the model flat on to an image plane. The image you put there is the texture.
Baking is the method of transferring information from high poly to low poly model with the use of UV image.
Now go look up those terms.
thanks for the video, great help man 
also sorry for double post i thought i pressed back when really it was just being held for moderator viewing my bad
another thing, if i were trying to do something less organic that doesnt necessarily require me to sculpt (a gun for example) how would that process work?
basically create a low poly gun… finish the basic modelling, unwrap UVs for it, then duplicate it and carry on adding finer details, once you have the high and low poly versions, baking AO, normals, and whatever else is exactly the same as the video.
personally i always use texture baking as an oppurtunity to make procedural textures such as cloud. wood, voronoi and other normally “invisible” textures “visible”… also its a sometimes a good idea to stick AO baking in there too…, realtime AO (although nowhere near perfect) sometimes looks good
(i always use baked textures for environment meshes, it keeps them fast and makes them look nice, just make sure you remove any object/mesh which will be animated first leaving JUST static environment meshes (so you dont get unwanted shadows baked into the mapping))