Get me started please

Dear coders, i am looking for some help for future projects.
First step i tried a slider as a ‘runner-up’. (no leds when 0, all pixels on when 1)
But i kept on getting errors.
The plan is to later replace the slider by an analog input from a potmeter.

For another project i am looking to use the timing functions.
Pixelcount should be divided into 12 sections and each section should dim-up during its hour. So that at 12AM (as well as at 12PM) all leds are on.
Can someone get me going? I must say that my coding skill is poor, but i guess you got that by now.
Thanks,
Jacob