In MachineBuilder, you can change your connection increments by clicking on the "45mm" in the units tabs in the top ribbon.
From there, you will be able to select your desired increment, down to 1mm. It's recommend to work with 22.5mm or 45mm increments for Vention parts to ensure proper alignment of parts and connection points. The smaller increments are most useful to connect custom parts.
Similarly, the angle connection increments can be changed by clicking "menu" at the top left corner of your screen, then "Settings"->"smart design"->"Snap to Angle".