Please help me configure my router to prevent access to my SSID using the mac filter

I am new to this, so please forgive me if I am completely incorrect, but I am currently trying to configure my router so that I can control which devices have access to my SSIDs.  I apparently have two SSID's--one is 2.4 Ghz and the other is 5.0 Ghz.  I am not exactly sure the significance other than the 5.0 should technically run faster.  I am currently in school and use my computer and wireless printer a significant amount; however, I have found that our network gets congested causing severely slow speeds and sometimes the inability to connect to the printer at all.  

Please correct me if I am wrong, but I was hoping to limit my roommate's to the 2.4 ghz channel which would allow me to have sole access to the 5.0 ghz channel.  Would this actually make a difference?  If so, how do I go about using the blacklist option to prevent the two mac addresses from accessing that channel?  I thought I was on the right track, but then I do not see "blocked."  All of them say "allowed."  The only difference is the presence of the the asterik.  Can anyone point me in the right direction or offer any advice.  Thank you.

I am using a BGW210-700 Modem/Router on a macbook pro running Sierra.  Also, are there any specific settings I should use to optimize the speed of my network?