Here's the ball joint (track rod end), circled in red.
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You will need to disconnect it from the steering arm (which is part of the swivel pin) and the steering rack.
To remove from the steering arm, you have to undo the nut below it, and split the taper fit joint. This can be done with brute force and ignorance, but is best done with a ball joint splitter if you can beg or borrow one.
Getting it off the steering rack can be tricky, they tend to get well stuck on, especially if the thread wasn't greased when it was fitted. It may require further brute force, heat, penetrating oil, or down-right destruction to get the track rod end off.
With the locking nut undone, you have to unscrew it off the track rod (end of the rack).
If you're careful, and lucky, the new track rod end will be the same length as the one you take off. If so, leave the lock nut in place on the track rod, so you can use it as a guide to wind the new track rod end on as far as the old one was. The position of this affects your tracking (toe in/out of the front wheels when viewed from above or below), so it's important to get it right. If you're not sure, it's best to get it rechecked after doing the work.