For some reason,
Updating my apps using App Lounge hang on the app Signal showing status “INSTALLING” and never proceeded - which also hindered other updates. It did not help close all apps, reboot, try again.
So I uninstalled Signal (kept user data), and then all apps could get updated.
Then i installed Signal - worked right away - an expected it to automatically find its existing user data.
It did not! - did not even ask. 
It asked me if I have my old phone (assuming it runs on a new phone i bought) meaning another one, with Signal installed that could scan this phone in next step where Signal here show a QR for verification), or “I do not have an old phone or I reinstall on same). I chose the latter. But then it need either a 64 char key for a copy on cloud (i had no idea) or a local backup file (it seem not to care about already existing app adata left by previous installation…)
I don’t have very important things stored in Signal.
I proceeded to make a new account
Anyhow, i thought i should warn others that keeping app data when uninstalling temporarily dont help.