I found a place I can recruit Grasans on the Gateway Island, but when I try to recruit them it says "Requirements not met" How can I recruit one?

The limiting factor for most new players in recruiting those Grasans is Worldly Inertia (sometimes referred to as value points). New accounts usually start with around 1000 maximum WI and can increase that maximum through various means. However it is possible to gather WI higher than your maximum, the easiest way to do so is by fighting someone, though there are other ways too. You can see how much WI you gained from a particular fight in the "results" tab of a fight log. Watch out though, if your timer (top-left of the interface) ticks over while your WI is higher than its maximum it will be lowered back to the maximum, so be sure to plan accordingly.