Well done ! you installed the system image on the memory card of your raspberry, you now have two options:
OPTION 1 (Recommanded): Use the connected version, it has the following advantages
Follow the steps below :
NB: At launch, the system checks if an internet connection is available, in this case it launches the online version, otherwise it switches to the offline version
Use the offline version, just plug the raspberry on the screen, the software will launch itself.
Important : The Raspberry does not have an RTC clock (an electronic component with a battery) which allows keeping the time correctly set when it is off.
So it is advisable to equip the raspberry with RTC if you do not plane to connect it to the internet, this will avoid loss of system time in the event of a power failure. Just plug it in as illustrated below and type the following command in LXTerminal
sudo date -s "2020-03-31 11:03:07" && sudo hwclock -w