I use my Zebra for it usually, used my laptop once and it all worked. It's a pretty short time frame per my store's HR ETL, with requests having to be in my 10 a.m. on Monday. (Don't know if it's company-wide, or just her.)
From the menu, choose "My Requests," then "New Request," then I think "PTO Vacation." (Sorry, but I'm probably not getting this exactly right. Think you'll still get enough of the gist to do it though. There aren't many options per step.)
I make my request for the Saturday of the week just ended and the starting time as whatever, even though I worked my full shift for that day. Don't think it matters, but you have to pick a day and a start time.
You have to be sure to have enough accrued hours for what you're requesting. Press "Submit" and you should be good.
Seems like HR leads should be expecting a fair number of these requests, considering how many of us work Sundays and would otherwise be out a day's pay.