The fore end is drilled for the mag tube so it has to slide off the tube, or more correctly the tube slides out of it.
The screw in the end cap (on a rifle) or rear barrel band (on a carbine) fits in a hole split between the barrel and mag tube, securing the mag tube and fore end in place. The forward band screw on the carbine has a similar function and secures the tube and barrel at the muzzle end.
Removing that/those screws lets the magazine tube slide forward to free the fore end. And, once the tube is removed, the band (on a carbine ) will clear the front sight if you see a need to remove it. The forward end of the tube on a rifle is secured by a hanger and it's fixed in a dive tail.
Some rifles and carbines have for ends that are very firmly stuck to the receiver when new but over time they shoot loose and are easier to remove. If yours is stiff go easy on it, but it will come off pulling straight forward.
Removing the fore end is a good idea on a Rossi as they are prone to rust along the barrel from moisture in the very poorly sealed fore end.
The mag tube is a routine cleaning item and you do that by removing the screw in the side of the tube that secures the plug in the end of the mag tube. Once that screw is removed, the plug just comes out. If it's new and fully equipped with factory new grime, it will probably stick and need to be wiggled a bit, but hold it in the tube any way as normally the magazine spring will launch them across the room. Once the plug is out, remove the mag tube spring and the follower will normally come with it.
The yellow plastic followers eventually fail as they tend to expand over time and collect grit which eventually causes them to hang in the tube. You can get a metal one from Stevesgunz.com for reasonable money. Once the tube and follower are out, just use a cleaning rod and large patch or suitable swab to clean the gunk out of it. There will be loads of cosmoline, gunk and rusty colored stuff in a new Rossi mag tube.
Carbines, Short Rifles and Rifles:
Nomenclature wise, Winchester lever action "rifles" had end caps and barrels 22" or longer. The rifle barrel profile could be round, half round or octagon. Rifles also had either straight (shot gun) butt plates or cresent butt plates. "Carbines" had round barrels (no exceptions on that) and front barrel bands with no end caps. Carbines originally had curved butt plates (not to be confused with a cresent butt plate) like the current non-.454 Rossi carbines. Later carbines had straight butt plates.
Lever action Winchesters with fore end caps and barrels of any profile and less than 22" in length are "short rifles", not carbines.
There are also muskets, but those are pretty obvious in terms of longer fore ends and barrel bands. There are also the occasional special ordered lever guns encountered but the above rules will cover about 95% of what you'll run into.