On MyVoipTiger you select PBX and then Dial Restrictions from the menu at the top of the page and you will arrive on an overview page of your existing dial restrictions. If this is the first time you are logging into MyVoipTiger, no dial restrictions will be shown.
You can add a new dial restriction by clicking on the relevant button. On the following screen you attribute a name to the dial restriction, select the members of the dial restriction (i.e. to which SIP accounts does the restriction apply) and you specify the allowed destinations for that dial restriction. You can select multiple destinations at once by holding the Control-key while selecting the destinations. Finally, click on Add and you are automatically returned to the overview page of your dial restrictions where the new dial restriction will already be shown.
To delete an existing dial restriction, go to the line for the dial restriction in question on the overview page and click on the icon of the trash can at the end of that line. When you have confirmed the deletion of the dial restriction, you are automatically returned to the overview page of your dial restriction(s) where the dial restriction in question will no longer be shown.