For those people who want to help recent disaster victims and are not affiliated with an organization, the National Voluntary Organizations Active in Disasters — NVOAD is the place to go. States also have a VOAD group.
That organization offers several helpful guidance documents on their website. Here is the direct link to their Recovery Guide. which is 96 pp.
[So far, the two best guides on recovery I have seen lately are this one from NVOAD and the Red Book, cited earlier.]