If you want to learn how to read a blueprint, there are a few things you need to know. First, blueprints are drawn to scale, which means that each line on the paper represents a specific measurement in real life. For example, one inch on the paper might represent one foot in real life. This is why it's important to use a ruler or measuring tape when looking at blueprints.
Second, blueprints usually have a north arrow somewhere on the page. This is important because it helps you orient yourself when looking at the drawing. The north arrow shows which direction is north, so if you're standing in front of a building that's represented on the blueprint, you can orient yourself by lining up the north arrow on the paper with North in real life.
Third, most blueprints will have dimensions written next to lines representing walls or other features of the structure. These numbers tell you how long or tall something is supposed to be. For example, if a wall is shown as being 10 feet long and 6 feet tall, that means that in real life, that wall should measure 10 feet from one end to the other and be 6 feet tall from floor to ceiling.
Finally, Blueprints often include symbols that represent different types of materials or objects. For example, a square with diagonal lines through it might represent glass windows, while circles might represent plumbing fixtures like sinks and toilets. By becoming familiar with these symbols, you can begin to understand what everything on the blueprint represents without having to ask someone else for help.