snom phones support the adding of contacts into a directory, making it simple to dial people you regularly call. We recommend that you do this from the web interface of the phone - for help logging in to this please see this article and video.
From the web interface select Directory from the left hand menu. Enter the name and number and then Add to add the contact to your directory.
If you have a lot of contacts to upload, you may prefer to upload a CSV file. The file format needs to have fields separated by commas - you can prepare this in any spreadsheet software such as Microsoft Excel or Libre Office. Ensure that names and numbers are added in separate columns in your file.
n.b. spreadsheet software will automatically remove entries starting with a zero. This is a bit of a problem when trying to enter a phone number! You can get around this by saving the field as text. Either enter the number starting with an apostrophe, for example:
Alternatively select the whole column, right click and select Format Cells and select Text as the cell format.
When you save the file select CSV as the file type. You will often get some warnings about saving in this file format, it is OK to ignore these.
You may also find it useful to open the file in a simple text editor such as notepad first to ensure it's in the correct format and that the entries are separated by commas as you expect.
To upload the file, return to the directories area of the web interface and use the import section to upload it.