How to set 10 Mhz band width with LEDE

Installing and Using OpenWrt Network and Wireless Configuration
1

Dear all
how to set 10 Mhz band width using LEDE firmware
since 2,4Ghz with 20/40 Mhz is very crowded
Thanks in advance

2

Same question: echo 10 instead of 5.

See: 5 Mhz bandwith option?