Manuel,
When you installed SolidWorks you were given the opportunity to allow dimension changes from the drawing. Most of what I do is ordinate dimensioning; there have not been any problems with this method.
Because you are new to SolidWorks I would like to recommend, if you have not done so already, is to create a template and put the title block information in the properties. Do not enter your title, names, dates, and etc using text. If you are interested check out thread thread559-23230
Bradley