mysql foreign key insert - mysql

Question

Using this two tables i'm trying to create a query to insert a new course, but i'm using a foreign key and I don't know how to pass that users(table) id into courses(table) id.
I'm trying to get something like this
I'm completely lost, on how to insert data into a table that contains a foreign key,
what i'm trying to do is:
first a person can register(user table)
2.Then the user will be available to add courses ( im using the foreign key to identify the courses for a specific user)
Users table
id | username |
---------------
1 | test |
Courses table
coursesid | coursesname | id(same id that in users table)
1 | courses test| 1
The Create Table commands are
CREATE TABLE `users` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`username` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
`password` char(64) COLLATE utf8_unicode_ci NOT NULL,
`salt` char(16) COLLATE utf8_unicode_ci NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `username` (`username`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1;
CREATE TABLE `course` (
`courseid` int(11) NOT NULL AUTO_INCREMENT,
`coursename` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
`id` int(11) NOT NULL,
UNIQUE KEY (`courseid`)
FOREIGN KEY (od) REFERENCES users(id)
)

Answer 1

You can use subquery for find user id, e.g.:
insert into course
(courseid, coursename, id)
values
(1, 'test courses',
(SELECT id FROM users where username = 'test')
)
;
Of cause, if you know user id, you can insert directly this id:
insert into course
(courseid, coursename, id)
values
(1, 'test courses', 1)
;
Additional query for insert just last user id:
insert into course
(courseid, coursename, id)
values
(1, 'test courses',
(SELECT max(id) FROM users)
)
;