You are going to need 3.5 inch casing so you can cover the gap at the top of the door. I can't tell for sure from the pic but do you have 3.5 inch casing on your existing doors across the hallway so it can match?

The door you are looking at is prehung so you are good to go. A power miter saw will be a big help for the door casing trim work but just doing one door you "could" get by with a hand saw and mitre box. But with cheap power miter saws for around $100 get a saw.

I skip all the shimming on an interior prehung door frame.

Install the door trim on hinge pin side of the frame before installing it.

Set it in the opening and adjust till the reveal between door and frame is even all around and then nail the trim to the wall.

Then just install door trim on other side of
frame.

No shims or level needed.

Just be thankful it isn't a pocket door.
Now those are a handful.