Need Help With Harding WordPress WP Security Scan

I installed the latest stable version of wordpress & the plugin
WP Security Scan & it’s telling me to fix the following two errors.

Your table prefix should not be wp_. Click here to change it.

The file .htaccess does not exist in wp-admin/.

I changed my permalinks to /%category%/%postname%/ could that
be causing some of the errors anyway how do I fix these two errors.