It seems you did not uploaded any scripts yet.
1- Please upload the script with reboot command
2- Select the uploaded script
3- Click on "Execute" and there you will get the "Checkbox".
If you try to schedule a reboot script then you will not get the checkbox but it will let you schedule it. I haven't observed yet if scheduling a reboot script works but will test and update.
Syamantak Omer | Community moderator | Sr.Staff TSE | CWNA | CCNA | RASZA | RICXI