The use of 'SE'?
 

I don't really understand the use of the word se in some one the cases.
I understand it's a word for activities that happen generally, not necessarily right now, for example: "como se llega a la plaza?".

but here are examples for sentences where I don't understand:

"Esta pelea, puede durar mucho tiempo y termina cuando una de las personas se rinde."

'El turista se le acerca y busca conversar con él. '

what the se is used for? thank you !

The pronoun 'se' is used a lot of different ways. Your sentences demonstrate a couple of them.

In the first sentence, 'se llega' means 'one arrives'. This usage is known as "impersonal 'se'." When no particular person is being addressed, use 'se'.

In the second sentence, 'se rinde' is the conjugated form of 'rendirse', which is known as a pronominal verb.
It means 'gives up' or 'surrenders'.

In the third sentence, 'se' is used pronominally. 'Acercarse', the unconjugated form, means 'to get close', so 'se le acerca' means 'gets close to him'.

There are several uses of 'se'. You can search online or here in the forums for:
object pronoun substitution (when next to another third-person object pronoun)
passive 'se'
accidental (no fault) 'se'
reflexive 'se'
reciprocal 'se'
pronominal 'se'
impersonal 'se'
process 'se' (examples are 'casarse', 'rendirse' or 'despertarse')

And there are some pronominal verbs that take on a meaning that differs from the meaning of the plain infinitive (without the pronominal object), like 'irse' (to leave, go away) or 'pasarse' (to spend time [doing something]).

This is really helpful thank you !!

You're welcome.