Note: Design Rule checks are always carried out using the full precision of the program, but will always be rounded to the selected precision for report purposes.  In some cases it may be helpful to visit [Settings], [Units] and increase the number of available deimal places.

After you have checked your design using DRC, you will need to take account of any errors that DRC has found. A DRC report is created in your chosen location which may be configured under [Settings], [Preferences].  It's in the 'Report' section in the right hand column of the 'General' tab.  Use <F1> if you need more detailed help with this. The report can be viewed on-screen at the end of the DRC check, but possibly the easiest way to work your way through the errors is using the 'Goto' bar (see below).  An alternative is to use the hot keys <T> (next error) and <V> (previous error).  In all cases the program will zoom out to the extent of the error but will not zoom in so it can be helpful to start with a fairly close zoom level.

The Goto bar can be opened from the [View] menu, [Dockable Bars], [Goto Bar]. From the dropdown list at the top of the bar, choose Error. The error markers are listed in layer or type order (depending on the settings). Clicking on any of these errors will take you to the error location in the design, where you can then work out what needs altering to remove the cause of the error.

As you make the adjustments needed to correct an error (perhaps by moving an item, or adjusting the spacings), you can if you wish delete the error marker so you can see how far you have got. But remember, deleting an error will not correct the cause of an error, you have to edit the design items themselves and re-run DRC to verify that the error no longer happens and you have not inadvertently created a new one.

Another scenario is that you can't correct the error.  Perhaps the necessary spacing on a footprint is too small for the normal pad to pad spacing, for instance..  In this case you can right click on the error and mark it as 'Accepted'.  It will normally remain visible, but you can change that.  Go to [View], [Display] and select the 'Layers and LayerSpans' tab.  Scroll to the extreme right of the top table and double click on the 'Yes' box at the intersection of 'Displayed' and 'Accepted Errors.  This will toggle to 'No' and hide any accepted errors.  Please note that this setting is NOT global.  It needs to be done for any affected designs, though if you're using a custom technology file, you can set it up there as well.