How to do a surface CE with maps?

Hello, I want to do a surface CE, the size of the slab is fixed, for example, 11 layers and 4 atoms per layer. I also want to fix the position of some atoms with ‘F F F’. How should I write the lat.in and vasp.wrap ?
Thanks a lot

I’ve answered this before, see https://alum.mit.edu/www/avdw/forum/viewtopic.php?f=4&t=521&p=1728&hilit=surface#p1728