Changing defauls in 2019

[BernieC]

I'm a complete newby to 2019 -- I just upgraded from Visio 2002!!. One thing I'd like to do is set up the defaults for the kind of charts I make. In particular, I"d like to change the default font,, I'd like there to be a grid, I'd like to make the default fill for shapes to "none". I *think* I can do that by setting up some new/custom theme (?? stencil??) but that machinery seems to be pretty new and is beyond my stone-age visio expertise. And help/advice would be appreciated. Thanks