Hindi lahat steps sa pag downgrade ng Windows OS ay pare-pareho. It is ALWAYS advisable to properly research. Much better din na mag backup ng files before anything else. Do not trust the program to always work 100%. Buti na yong laging handa kesa mamoblema.
Once installing, current os installation will try to detect previous os installed, if detected it will prompt you to either
leave as is or remove. If leaved is selected and finished installing os, you will have OLD.Windows folder on drive C:
there you can access all your data.