Nobody is in the tree yet except you.
Start by adding your parents, or anyone you remember.
These people registered and are waiting for a relative to let them in. Anyone already in the family can decide — you don't need to be the one who sent them the link.
Keep a copy of the whole family tree somewhere safe — your phone, Google Drive, a USB stick. If anything ever happens to this app, any of these files can bring the family back.
Everything in the app, for restoring it. PINs are never included — after a restore, each person picks a new one when they sign in.
Opens in Excel or Google Sheets. One row per person, easy to read or print.
A GEDCOM file — the standard every genealogy app can open. Private notes are left out of this one, since these sites can be public.
Puts back anything that is missing. It never deletes and never overwrites what is already here.
Only a first name or nickname is required. Anything you are unsure about, write it as you remember it — "about 1940", "died young", a question mark. Nothing here has to be exact.