There are some very good tutorials in .pdf format available from Freestuff. For very basic instructions maybe one of these might help.

https://www.renderosity.com/mod/freestuff/dynamic-cloth-tutorial/75014

https://www.renderosity.com/mod/freestuff/cloth-room-tutorial/59882

For more detailed instructions and helpful tips Frequency has a series of tutorials:

https://www.renderosity.com/mod/freestuff/contributor/Frequency

Always remember to save your scene before running a simulation!