What i usualy do after installing {flavor} of ubuntu.

ubuntu-install.log

#Check ubuntu version with
cat /etc/*release







#Go to sudo and update repo
sudo su

#Replace .rs in sources.list
sed -i 's/rs.//g' /etc/apt/sources.list
apt update

#Remove unused things
apt purge firefox* libreoffice* gnome-orca* deja-dup* atril* rhythmbox* pidgin* thunderbird* plank* pluma* shotwell* synapse* 

#For this core packages better use remove than purge ...
apt remove ubuntu-mate-welcome mate-utils simple-scan popularity-contest

#Now update system
apt dist-upgrade

#Install Google Chrome
wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
gdebi google-chrome-stable_current_amd64.deb

#Install Atom
wget https://atom.io/download/deb
mv deb atom.deb
gdebi atom.deb

#Basic utilities
apt install synaptic filezilla vlc git curl unrar leafpad

#Install Adapta-Nokto-Eta and icons PPA
apt-add-repository ppa:tista/adapta -y
apt-add-repository ppa:noobslab/icons -y
apt update
apt install adapta-gtk-theme arc-icons

To fix mdam "mdadm.conf defines no arrays"
Just add this to your /etc/mdadm/mdadm.conf (change /dev/vda1 to your mountpoint "cat /proc/mounts")
ARRAY <ignore> devices=/dev/vda1
and then just run "update-initramfs -u"

Update1:
Someone posted better 1 line solution on serverfault.com
grep "ARRAY <ignore> devices" /etc/mdadm/mdadm.conf >/dev/null || echo "ARRAY <ignore> devices=/dev/vda1" | sudo -A tee -a /etc/mdadm/mdadm.conf >/dev/null;