Use Guided Modeling
Guided Modeling supports you in placing or moving items. When you place or move objects or connections in a model, lines and arrows appear informing you of the orientation and distance of the items from adjacent items. The items snap into place at the position suggested by Guided Modeling. If Guided Modeling and the grid are enabled, Guided Modeling has priority when you position items.
You can enable or disable Guided Modeling, which uses lines and arrows to help you place objects or connections at the selected distance in the modeling area.
Open the model.
Activate the Model tab bar.
Click
Modeling area.Enable
Show guides or disable 
Show guides.
You have enabled or disabled the guides for Guided Modeling.
You can set the default distance for Guided Modeling. Thereby, the layout of the current model is changed, but you can undo the change. Changing the default distance affects future layout operations.
In an open model, activate the Model tab bar.
Click
Layout. The layout options are displayed.Enter values for Horizontal item spacing and Vertical item spacing.
Keep the Use as default check box enabled.
Click OK. The layout options are applied.
Check whether the new layout meets your requirements. If not, click
Undo. The layout operation is undone and the model looks as before.
The item spacing you entered is set as the default distance. When you place objects, the default distance is indicated by the following cursor: 
When Guided Modeling and the grid are enabled, you can temporarily switch off Guided Modeling and the grid when dragging items.
In an open model, select the item you want to drag.
Press the Alt key, then drag the item to the required position.
The item is not fixed by Guided Modeling and/or the grid and can be moved pixel by pixel. Depending on how you want to align objects, you can disable the grid and align objects using Guided Modeling only.