First you should create an account this will send you an link with your login credentials per email. No frills login, no password, you have to have cookies accepted, thats all.
uWiki uses an ACL system, in the following text I assume that you have privileges to do something. If not you will get an error page instead.
When a pages doesn't exist you are send to a create form. with the uri _uwiki/create/…. you can explicitly create pages.
For each /foo you can enter /_uwiki/edit/foo to edit the page. You can test in the Sandbox
_uwiki/recentchanges/…. gives the log for the path ….