Signing players not drafted
Does anybody know what the process of signing players who weren't drafted is? I assume that they are all FA's now, but can any team sign one of them right away? Is there a date at which they become available? Is it necessary to be under the cap? I know that the Kings were interested in Randle, and they have open spots on next year's roster, so could they offer up a contract equal to that of the 60th pick and sign him right away? It seems like there were quite a few players who went undrafted who could find space on either Sacramento's or Miami's roster. Thanks in advance for any responses.