I use RapidSVN on Ubuntu, it is free, in the store, has a good GUI and is very easy to install. I understand it is also available for windows at https://download.cnet.com/rapidsvn/3000-2352_4-75182502.html although I have not used this version. I first needed to get into SVNs as a result of creating a WordPress plugin. WordPress require you to publish your plugin via their SVN. I was completely baffled and had no idea. There is a selection of tutorials at https://diversify.me.uk/how-to-use-the-wordpress-svn-quick-start-tutorial/ which not only deal with the basics of SVNs, but RapidSVN in particular and using it with the WordPress SVN.