Please realize that what you show above is non-standard. What it appears to be doing is walking you through the process of connecting to a database in a step-by-step manner. What you are showing are prompts asking for a specific piece of data. The first prompt is asking for the host you wish to connect to with a default value of localhost. Then port, with a default of 5432. Database, default postgres. Username, default postgres. Assuming all of the defaults are valid what happens if you simply hit enter for each of the prompts until you get to a prompt that is for something other than a setting with a default value?
Typing in \l or \dt at one of the above prompts is non-sensicial. Whatever you are running is not yet ready to accept generic commands. Likely even when the prompting is completed what you end up with will not be a generic psql shell where these meta-commands will have meaning.
You should learn what "Shell" (its seems more like an application) you are using and ask whomever wrote it what you should be doing.