If you are using the most up to date then the way the shapes are installed and loaded into has changed, there is no longer a load or replace or a particular need to have a location for the presets as they are now all imported into the applications the same way as the gradients import / load as well as the strokes etc. Goto the shapes panel found in the window menu. Goto the right side menu at the top of the panel and go to the import and browse for the CSH files. Select and the presets will be added as a group in the panel. You can then move those presets around as well as select them and delete them.
If you are using an older version of Photoshop then the shapes panel has a right side menu with load / replace commands and also a selection of files found in the default installation folder. You can access all the presets via the load / replace commands and browse for CSH files or just select a file
There is no need for this with the latest version of the application as all the files are imported and reside within the application. In earlier version, the files were location in the applications (or Program files) / Adobe Photoshop xx / presets / custom shapes folder
You can also add the presets and access them via the panel in your own user account section and on the mac that can be accessed via the ~/Library and application support (on the PC it is the appdata folder just to confuse). Go to the adobe and the adobe Photoshop xx and then presets and then custom shapes.
You can quickly add multiple vector presets into the application via the command. Simply browse for the files and then select multiple entries and click OK. Once they have been added, you will see each of the CSH files in their separate groups based on the name of the file. You can move the items, delete them as required. https://youtu.be/RyPnpqj4jcs