Hello there. Yes, one tip to keep in mind is that you need to back out the rollers and upper guide if possible. Then tilt the door to remove or replace it. Take a look at this video, it shows the 23-225, roller being placed in the track, take notice of how the little guide clips slip into the channel, this might be where you were getting hung up.
The 23-041 roller is most commonly held in the door by its hooks. In order to remove it, you will first need to take the door out of the frame and place it on a stable surface, like a table or the floor. Then, use a pair of pliers to grip the roller housing and gently--but firmly--work the hooks out of their slots.
There's no real trick to it beyond that. The hooks will be pretty firmly installed so it may take some time to work them out, but as long as you're patient and persistent they should hopefully unhook with little issue.
