Trying them is quite simple, but urob's config repo is using macros for ZMK that might make it a bit difficult to adopt it to your own, regular ZMK config.
Add the hm_l, hm_r, hm_shift_l, hm_shift_r behaviors to your keymap
Reflash your keyboard and you should be good to go.
2. Try his combo improvements
While you are at it, you can also try his combo improvements.
The new global-quick-tap-ms = <75>; settings makes it so that if any key was pressed within 75ms before the combo hit, the combo won't be run and instead the keys will register as taps.
This significantly reduces accidental activations during typing and made combos finally usable for me.
3. Try num word (caps word for numbers)
This one has been a game changer for me. I put it as a tap on my right outer thumb and now after tapping the key, I can just start typing numbers with my left side num pad layer.
The layer automatically deactivates as soon as I hit any key except for numbers, dot, comma, star, slash, plus, minus and equal.
So I can press my <&num_word> key and type 20/5=4 and the number layer automatically turns off as soon as I type the space.
You can also use it with any other layer using his smart-layers-for-zmk feature.
I am loving it for my nav layer to. I activate it using a tap dance.
BONUS: caksoylar's keymap-drawer
And finally another cool software (that is not made by urob) you may also be interested.