Retirement involves a period of adjustment, of finding ones feet in a new situation, and I think good advice is not to rush into too many things at once, but allow yourself time to adjust to this new phase of your life and then do only what it is that you enjoy, and if that involves periods of pottering at home then that is absolutely fine, and there's no reason to feel any guilt for doing so.
It is important to try and get outdoors each day of course, for exercise and fresh air, whether that's to potter in the garden, go for a walk or maybe a swim or similar, if you are physically able to do so in order to keep active and keep those myscles working, but off "doing" things such as being on committees, joining groups, volunteering, isn't for everyone and if you prefer pottering in the home rather than doing these things, then that's fine, too.