[U-Boot] Adding a new device to my project

Hi, I have a general U-boot question that is causing me confusion.

I am adding a new device to my existing project. So I assume that I'll need to rerun config (i.e.: make target_config). Correct?

I have a .h file in the include/configs directory. I need to modify it to add my new config such as: #define CONFIG_DEVICE_FOO 1 Correct?

Then how does include/autoconf.mk get recreated? The last time I tried to do this, I spent a hours trying to rebuild my project that I broke.

Sorry for the "dumb" uboot question. thanks in advance, Steve