In Mike X Cohen YouTube channel you can find a lot of interesting video lectures about the EEG signal and EEGLAB Toolbox. This playlist is a very useful introduction to the field:

https://youtube.com/playlist?list=PLn0OLiymPak2Jonu3CNTCKxKMNWgz3CTC

Of course, you can find more advanced video lectures about different topics in the same channel.

Thank you so much David López-García

EEGLAB also has it's own Youtube channel and has a number of Tutorial videos that cover all different EEGLAB functions.

https://www.youtube.com/channel/UCK8x1bdiHWmT0yCNEjTcEvA

Their website also has neatly organised the youtube videos starting from basic to more advanced stuff - I found it very helpful for my own learning

https://eeglab.org/workshops/Online_EEGLAB_Workshop.html#preprocessing-data-in-eeglab-2018-delorme

Thank you so much @Ty Lees and @ Vasileios Ioakeimidis

Dear Md. Humaun Kabir

To learn EEGLAB, Follow the EEGLAB Channel on Youtube. The creator of EEGLAB (Arnaud Delorme) himself explained all the ways to process EEG data in EEGLAB.

The Playlist link is as follows:

1. https://www.youtube.com/watch?v=R_nf1HRScx4&list=PLXc9qfVbMMN2NksmDeqizCI1z5DJBlqC6

2. https://www.youtube.com/watch?v=gEk33jWB0MY&list=PLXc9qfVbMMN1ZS3sU2xT2hhfB5PAmuNae

3. https://www.youtube.com/watch?v=kWAjhXr7pT4&list=PLXc9qfVbMMN2uDadxZ_OEsHjzcRtlLNxc

Hope it will help you.