sudo pacman -S yay

where pacman is the default package manager, yay is aur helper wrapped around pacman. Here is the link : https://aur.archlinux.org/packages/yay

yay -h

for general help and

yay -[S|Q|R|...]h

where S = Sync, Q = Query, R = Remove

yay -Scc
yay -c
yay -Ss __regex__
yay -[S|Q]i

where S = remote info, Q = local info

yay -S __package__
yay -Qe
yay -Runs __package__

where u = unneeded packages, n = remove config files, s = unneeded dependencies