package management - Can't install xdman using APT - Ask Ubuntu

I tried to install xdman using sudo add-apt-repository ppa:noobslab/apps sudo apt-get update sudo apt-get install xdman but I can't download it; I get this: E: Could not get lock /var/lib/dpk

I accidently pressed F11 during startup, and now i have this. How do i go back? : r/Ubuntu

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