Hi @Baris,
I do not see any problems on the description you posted above.
Please, consider to run the following commands in the terminal.
We use pacman-mirrors to set a mirror and the desired branch.
# pacman-mirrors --api --set-branch unstable --url https://manjaro.moson.eu
You can replace the branch with stable or testing and you can remove the –url argument and use e.g. –continent for closer mirrors or leave it out for a complete run against all mirrors.
4. Database and keyrings
Download the databases and install keyrings
# pacman -Syy archlinux-keyring manjaro-keyring
5. Trust database
Create trust database, populate and refresh keys
# pacman-key --init
# pacman-key --populate archlinux manjaro
# pacman-key --refresh-keys
This instruction where extracted from the following post created by @linux-aarhus , who is part of the Manjaro Team.
‘[root tip] Do a manual Manjaro installation’