Laravel Relations foreign key

$table->bigIncrements('id'); $table->unsignedBigInteger('siswa_id'); $table->string('name'); $table->string('email')->unique(); $table->timestamp('email_verified_at')->nullable(); $table->string('nik_nisn'); $table->string('type'); $table->string('password'); $table->rememberToken(); $table->timestamps(); $table->foreign('siswa_id')->references('id')->on('siswa');

how do i do relations in users table? while the email field is unique, when I keep trying an error occurs. maybe the error appears because the email field is unique. Any suggestions for me?