How to change start date?

See guys, I start my entries and their date turns red and when I press summary no amount are shown and I guess it was the start date but I just don’t know how to change it please do help me guys.

What do you mean by I start my entries ?

Setting start and period reporting dates is explained in these guides

Set reporting period

Set start date

go to setting tab there is an other icon for start date. there you can put your start date and start working.

please give screenshots about that.