Ah sure, happy to provide some guidance!
So Breww generates an A4 label document with the exact specifications of the recommended Avery label size. Unfortunately, however, every printer is slightly different and in addition to that are manually configurable by the user, so settings can vary a lot - and there are a variety of settings that might cause the document generated by Breww to not quite line-up perfectly with your labels.
To combat this Breww provides a number of “A4 Label” settings, that can be configured in Settings > Label settings. These allow you to tweak the margin, label widths and column spacing on the label PDF document that Breww generates, until it’s perfect for your printer’s specific set-up.
For example if the labels are being printed too closely together, you can use the “Horizontal label spacing” to tweak it in mm until it is perfect.
Hope that helps! But anything else just shout!