The petition asks for all cleaning in the locality to be done with environmentally friendly products. If you have signed a change.org petition before all you have to do is click where it says "imzası" All your details will have been saved.
If not, on the right where you sign it will ask for your name "isim" and then your address "adres" with a drop down box for country and an option to add comments. The just click where it says "imzası" I am doing this from memory because this page doesn't show again once you have signed so I hope its correct but I think you will get the gist.