Since it appears that you're in Clark county, you probably are planning on taking the tests at the North Las Vegas DMV for CDL? ...it used to be that you were required to take the non-commercial license test at the CDL testing offices (Carson City, Elko, Reno, Winnemucca, and North LV --they did away with the one in Tonopah several years ago which was the one I encouraged RVers to use as it was less busy, easy to access, and usually had good testing personnel).
At North LV it seems like it depends on who you get as the examiner so it apparently varies. We never had to take the test in Nevada when we became residents as we had CDLs from another state but we kept in touch with many RVers who did take the tests ...but this was over a decade ago when we were paying more attention.
Roy1 gives good advice in studying the official state study guide. I'm assuming you already have it but if not, I'll attach it below. It's from 2012 but still current as it's still posted on the state's DMV website.
One thing you'll most likely be asked to demonstrate during the road test is the air brake governor that is a standard CDL test on air-brake equipped vehicles (or as Roy1 describes as "the leak down test"). This is described on page 56 and there are dozens of videos illustrating it online for trucks, buses, motorhomes, etc. --1) the full application one-minute test, 2) fanning off air making the low-air warning buzzer activate at around 60 psi, and 3) continuing fanning off air until the parking brake knob pops out at about 35-40 psi.