To scroll down:
client
.url('https://www.yourwebsite.com')
.leftClick('#yourtable') // <-- should also work with .click()
.scroll(0, 500) // the higher the more we scroll
to use keys make sure to click on the list div box before that the emulated mouse is at the item you want to scroll down. Then you can press the down key to go down:
/*
\uE014 "ArrowRight"
\uE015 "ArrowDown"
*/
client
.leftClick('#yourtable') // <-- should also work with .click()
.keys('ArrowDown')
.keys('ArrowDown')
.keys('ArrowDown')
// or
.keys('\uE015')
.keys('\uE015')
.keys('\uE015')
Source: api/protocol/keys.html