If you are new to WP, chances are that you will have issues with your site. Do not panic, you can ask for help or google the exact problem/error you have, most of the times you will find many resources with fixes. From my experience 90% of the cases can be diagnosed easily though.
First things to try :
Disable any caching/optimization plugins, clear your browser’s cache!
Disable all your plugins or the ones you do not need to view/use your site.
Switch to one of the default WP themes ( twenty fifteen, twenty nineteen etc)
If you do these and still have the same problem, like not able to view your site or create a post, here are more advanced ways to find the problem.
Easy, you just rename the old xampp directory and install the new version. PhpMyAdmin works for each one so you can import/export your databases and your files! Doh! I was really worried about this for a long time and thought I should share my ‘solution’
The theme uses JointsWP 4.0 ( float grid ), I just updated WP to 5.0.1 and WC to the latest version and found no issues. Basically I added what the WooCommerce documentation recommends to make your theme compatible with WooCommerce, that is in the functions.php and a stylesheet ( woojoo.css ) for this style ( nothing special )