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The far most important tools to navigate across your model are 'ZOOMING' and 'PANNING'. You can zoom in and zoom out using the mouse scroll wheel. Push the right mouse button to pan the canvas. Sometimes a 'zoom to fit  (Ctrl+F) might be useful.   

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To pan the canvas, you can push the right mouse button. If you prefer to use the scroll wheel to pan, you can adjust this in the user preferences.

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Connecting the basic circuits with piping tools

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After the Ctrl+V action, the copied part of the system can be dragged to the desired location in the drawing canvas before pasting itdropping it on the canvas with Ctrl+D.

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Replacing components (Ctrl+H)

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