I am really strugging to learn how to draw digitally. 

I cannot figure out how to delete a part of a drawing without loosing all of it. 

For example, I have a square and I want to bevel one corner. I can draw the line when bevel should be but I cannot delete the corner. Or, I want to delete a section of square and I can plot the lines but I cannot fgure out how to delete that section.

Thanks,

Draw a line, draw a rectangle, put the line where you want to have the 'cut', select both (Line and Rectangle), them select Path -> Divide (or Ctrl+/).

You can break a path at every node you like and there's a button to delete segments between selected nodes. The Corner Live Path Effect will let you bevel specific nodes.

Thanks for the tips! I will have to continue practicing with program. I've never had any digital drawing lessons or experience. I wanted to draw a bracket that could be either machined or printed in plastic. A vendor I have worked with in the past drew up my idea easily enough with just a couple of minor changes so he will put in production for DIY project I am working on here at home. 

I don't see a link to add a photo direct to response so I have provided a link. Thanks, 

There‘s a paperclip icon for uploading attachments or simply drag it into the Editor Window and confirm.