Its not easy for someone who has to ask if it's easy. I'm Not being effrontic, it's nothing someone with a novice question would want to tackle. It's silicone and a couple of screws to some people, it's $1,000 of disrepair being rerepaired to others.
Any dealer with a service department can help you find the window and will have the Liability of refund if the wrong window is prescribed.
There's an excellent do it yourself thread here that may more fit the bill.
Someone better at the search feature will maybe post a link to the:
How to make the windows on an axis/Vegas open wider.
It's one of the easiest mods to do and theoretically triples the cfm.
Try this first and see if you like it.
We have a 24.1
With ONE front window in the cab open we find the bedroom drafts pretty well.
We have not done the wider opening window mod. I can, I haven't needed it. I will eventually, but it's not critical. First time I wash windows on the inside, it'll be done. It's almost that easy.