Hej Annebel,
In order to produce your survey follow these steps:
1. Design the survey using the Open Foris Collect application. If you install it and run it in your computer you can design the survey. Follow these videos on how to create a Collect Earth survey [VIDEO 1][1] and [VIDEO 2][2]
2. Generate the sampling design using this Google Earth Engine script (you can use your own shapefile with your area of interest by uploaing uploading as an asset in GEE or as a Fusion Table) : [GENERATE GRIDS THROUGH GEE][3]
GEE][3] . See [this explanation][4] on how to use it.
3. Add the CSV file generated through the GEE script to the survey (using the "Files" tab inside the Survey Designer)
4. Export the survey as a Collect Earth project file
5. To set the plot layout (25 meters square plot) [follow these instructions][4]
instructions][5]
You have some more info [here][5] [here][6] and a PDF tutorial [here][6]
[here][7]
Let us know if you have more doubts and also look through the support forum as there are many questions already asked!!
[1]: https://www.youtube.com/watch?v=Ml76no4XAdk
[2]: https://www.youtube.com/watch?v=j2ruGSzJg0Y
[3]: https://code.earthengine.google.com/e9e189545cbafe747984cc8d8042ac3f
[4]: http://www.openforis.org/support/questions/1605/creating-custom-project-ced-file-for-collect-earth
[5]: http://www.openforis.org/support/questions/1893/change-plot-size-in-collect
[5]: [6]: http://www.openforis.org/tools/collect-earth/tutorials
[6]: [7]: http://openforis.org/fileadmin/user_upload/Collect_Earth_Tutorials/Collect_Earth_User_Manual_20150618_highres_full.pdf