foreign key constraint, which table first

[x_wd11]

Which table do I insert to first, table1 that does have the FOREIGN KEY (file_id) REFERENCES userinfo(user_id) or the table2 that does NOT have the constrain?
 I am trying to insert into both tables at a sequence, table1 and then table2, BUT I get this error: "Cannot add or update a child row: a foreign key constraint fails...!"
Should I insert first into table2 and then into table1? Thanks

 $q1 = "INSERT INTO table1 ...
 $r1 = @mysqli_query($dbc, $q1); // Run the query.

 if ($r1) { // If it ran OK.
            $q2 = "INSERT INTO table2 ...
            $r2 = @mysqli_query($dbc, $q2);
            if($r2){...

[x_wd11]

I found this link https://codeburst.io/insert-with-select-statement-for-columns-with-foreign-key-constraint-in-mysql-with-examples-f9ab57c8e4dd and fixing some of the errors in my query I got it working.

[Larry]

Excellent! Kudos for figuring it out and thanks for letting us know.