In English you can say 'I'm going to do something' when you want to refer to a future action - you don't always have to say I will do something. And you can do this in Welsh too. Wendy flatly refuses to have Rhodri living with them full time. She says:

No way dw i'n mynd i dderbyn fod Rhodri yn byw gyda ni trwy'r amser.

'No way am I going to accept that Rhodri lives with us all the time'.

Now listen to other examples of mynd i referring to the future:

Dw i'n mynd i wrando ar Ysbyty Brynaber bob nos.
'I'm going to listen to Ysbyty Brynaber every night'.

Maen nhw'n mynd i brynu car newydd yfory.
'They're going to buy a new car tomorrow'.

Of course there is a future tense of the verb BOD - bydd. But bydd can also be used to indicate repeated actions as well as the future, as we learnt quite recently. Let me remind you of this usage. As Jenny reminisces about her time in Nairobi, she tells Michelle that Arwyn's local is the bar at the hotel where she was staying and that's where he usually drinks.

Michelle - Ydy e wedi ffeindio bar?
Jenny - Yfed yn 'bar' yr hotel lle roeddwn i'n aros bydd o gan amlaf...

Bydd here doesn't mean that Arwyn will drink in that particular bar but that he drinks there regularly - it's a repeated action. A clue is given to the meaning of 'bydd' here by the phrase gan amlaf - 'usually' . But be careful, a clue like this may not always be used.

Here are some other examples:

Bydd Arwyn yn mynd i'r ysbyty yfory Arwyn will be going to the hospital
tomorrow - this obviously refers to the future.

but

Bydd Arwyn yn mynd i'r ysbyty bob dydd

Arwyn goes to the hospital every day - this is a regular occurance

When Jenny admits to Agnes that she's feeling a bit low, Agnes asks her:

Wyt ti'n hiraethu am Kenya?

hiraethu is the verb from the noun hiraeth which is an almost impossible word to translate into any other language. It can signify sadness or grief after the loss of a person; or it can also indicate homesickness or the nostalgia for the old country, felt by so many Welsh people who have moved away from Wales. Hiraethu here means 'to miss' or 'to long for'. What Agnes asks Jenny is whether she longs to be back in Kenya. Can you guess why?