1) your username and password can be admin/admin, but you can remember it by going to: the database -> select the database -> click on the wp_users table and then enter the administrator record and update the password ( function uses md5)
Once the key has been changed go to: localhost/myweb/wp-admin/
Enter the user and the new password.
2) If your pages are in .php, you must do a process to insert the content to the WordPress database, but if you are a novice I recommend that you upload each publication one by one to WordPress.
3) Search on Youtube: WordPress for beginners WordPress courses from scratch (for beginners) there is enough material for you to learn about the WordPress administration.
If you have any doubts, do not hesitate to consult.