Premises also need support. Sometimes there are sub arguments for the premises. You should not confuse the sub arguments for a premise as part of the main argument for the main conclusion of the article or book you are reading. Premises for the main argument can themselves be conclusions of sub arguments. This can all be very complex since the author needs to justify the reasonableness of her premises, and this process could go on indefinitely. But we must stop the justification process at some point in order to consider the argument at hand. Sometimes support for a premise might merely be that it is "self-evident;" a reasonable question to ask would be whether or not the premise is in fact self-evident. Sometimes the support amounts to a clarification. So, you need to be aware of what the truth of a premise hinges on in order to evaluate the acceptability of a premise.
