It's a complicated process. First you have to create a password for the wallet. Then you have to import a key.

By the way, not advisable to run the wallet on the contabo server, for security reasons, especially if you are relatively new to linux systems administration. You should build a docker image or run in a virtual machine, but only build the cli_wallet (the steemit github will at least get you that far.

After you import the key, then you have to generate the brain key, save that somewhere safe, the pubic key goes into the update_witness command and the private key goes into the config.ini.

But I'm not going to be able to help you any further than that, I'm too busy, and also, I am draining the blood out of l0k1 and feeding it to elfspice, and this account will be intentionally abandoned in the future. My life has started a new phase and it's back to the roots.