Decreasing - can't understand pattern!

I’m working the back of a Bergere de France pattern and just cannot understand what they mean by decrease on each side 3 sts from edge as follows:
" 2 x 1 st every 12 rows, then 10 x 1st every 10 rows."
I do understand the mechanics of how to decrease and that I do it 3 stitches in but can’t see what the above sentence means!
Can anyone help please?

Hi Claire and welcome to Knitting Help!
It can be confusing when patterns use this shorthand. It might be easier as: dec at [I]each[/I] edge 1 stitch every 12 rows, twice and then 1 stitch every 10 rows, 10 times.
Anyway, it works out to be a decrease row on rows 12 and 24 and then on rows 34,44,54,64,74,84,94,104,114, and 124.

Hi Claire,

Don’t decrease on the edge, they are doing three stitches in to give a nice finished look. I have done several of these patterns and they take a little getting used to.

Decrease 1 stitch every 12 rows 2 times
Then decrease 1 stitch every 10 rows 10 times

If you still need help, let me know as I have most if their patterns.

Thank you both so much - I’m very frustrated that it all seems so simple now you’ve told me! I’m just going to have a go. Thanks again