Find channel that you want to download and copy it's URL.
For example : https://www.youtube.com/channel /UCe9Z8Gf_4pS3QNidDY_GI3A
Now just Select "Channel Download" from tab bar.
Paste YouTube Channel URL in appropriate text-box and click on "Download" button.
Wait until all video get processed and then click on "Download .txt File" button.
Go to Task->Import->From text file and import downloaded .txt file and check videos that you want to download and just click on "OK" button.