Creating brushes lightroom 3.1

Hi, 

I'm editing a wedding I did and wanted to smooth the skin, bring light in the hair and eyes. I use to have a lightroom version of around 2014. I've upgrated my computer and lost my brushes. I wanted to create brushses to do the same thing, but all the youtube videos and help on adobe don't seem to have the option to create a brush. 

I want to use the brush on multiple photos and be able to use it again later.

I've looked in the infos of my app and I seem to have Adobe Photoshop Lightroom 3.1, on a desktop macOS.

Can anyone help me please?

Thank you!