I've found a suitable photo - which bit are you trying to replace? If it's just the tensioner piston assembly you don't need to split the track.
Assuming you do need to split the track, if the tensioner piston won't go in once you've removed the bolt under the nipple, the easiest way is to let the vehicle do it for you - drive very slowly forward and let the track pull the piston in. Once that's done, find a way to stop the track moving once you split it, either the proper bar that sits between the return rollers or use a ratchet strap or hefty rope. You need the proper track clamps; the links must be at a ten degree angle to take the tension off the rubber bushes. Either use a drift or puller to remove the track pin. The track is very heavy and will have a mind of its own once released. This is not a one-man operation.
Andy