When you have Sangoma Talk on your cell phone, you can schedule it so that you will not get calls at configured times. 

First you will need to click on the settings gear. 

Next, you will need to click on Preferences. 

Next, you will click on Do Not Disturb.

Next, you will click on the plus side on the top right. 

You will then need to set the times you would like Do Not Disturb to be one and click Add.