If you are still getting JB coming up to December you should get a letter from the DSP informing you that it is coming to an end. It should also indicate options like applying for JA (means tested) or "signing" for credits. You need to indicate that the latter is your intention. Signing for credits is once a year. Yes, the same conditions apply as to being available for, and seeking, employment. At 60/61 I expect that some level of "activation" will apply - how this will impact you I don't know - as you will not be receiving any payment it may be quite limited.
The same conditions apply as long as you remain signing but activation is usually less after 62/63, eg, just information about workshops, etc.