Method 1 (Multicraft Config Files):
1. Log into Multicraft Control Panel
2. On the left hand side of your control panel click the 'Files' dropdown box
3. Click 'Config Files'
4. Choose the 'Server Settings' file that matches your server (for example, Server_Spigot will be for Spigot, etc.)
5. Change enable-command-block=false to enable-command-block=true
6. Click 'Save' then click your server
7. Restart your server and enjoy the command-blocky goodness!
Method 2 (Multicraft FTP Access):
1. Log into Multicraft Control Panel
2. On the left hand side, click the 'Files' dropdown box
3. Click the 'FTP File Access' option, log in when prompted.
4. In the folder list, click the appropriate server folder (for example, Server_Spigot will be for Spigot, etc.)
5. On the right side of the list, click 'Edit' in the same row as your 'server.properties' file
6. Find 'enable-command-block=false' and change it to 'enable-command-block=true'
7. Click 'Save', then click your server
8. Restart your server and enjoy the command-blocky goodness!