Welcome to the POB @lunacian, the issue your are facing is because of lack of resource credits. I would advice you to ‘Power Up’ whatever hive you get in rewards initially. To permanently increase the amount of resource credits your account can hold.
Alternatively you can also ask for some delegation of HP(Hive Power) from your referrer. Or buy some 3-4$ of hive and power it up.
Have a nice time here, if you have any questions you can ask them freely. We also have a discord, you can also join it if you want and get your queries answered there.
Best Wishes