New user created when i was trying to install bitname wordpress multisite 5.2

i was installing bitname wordpress multisite 5.2 and i did successfully but :
1- i cant find the folder where it supposed to have all the files or icon to open the server.
2- new user created under the name "mysql" which i dont know how it happened and i dont know what is the password for it.

i want to know where the folder is gone and how to use it.
how to remove this new user or how to know the password.
thank you inadvance