Ninapenda kusikiliza muziki wa redio wakati ninapika.

Breakdown of ninapenda:
• ni- = 1st person singular subject marker (“I”)
• -na- = present-tense marker (“am …ing” or simple present)
• penda = root “like”
Together, ni + na + penda = ninapenda, literally “I-present-like,” i.e. “I like.”

After verbs of preference (like penda), Swahili generally uses the infinitive form of the following verb. The infinitive is marked by the prefix ku- (“to”). So:
• kusikiliza = “to listen”
This makes ninapenda kusikiliza = “I like to listen.”

This is a genitive (possessive/associative) construction.
• muziki (class 3) = “music”
• redio (class 9) = “radio”
• wa = genitive link for class 3 nouns
Putting them together: muziki wa redio = “music of the radio” (i.e. “radio music”).

• wakati = “when” or “while,” introducing a time clause.
• ninapika = “I cook” (ni- subject + ‑na- present + pika “cook”).
Thus wakati ninapika = “while I cook.” You simply place wakati before a normal verb phrase to mark “when/while.”

• ninapenda spells out both the subject (“ni-”) and the tense (“-na-”).
• napenda is the colloquial contraction where the i of ni- merges into the n, but the meaning stays “I like.”
Both forms are widely understood, though ninapenda is more “fully” formed.

Yes. By adding the locative suffix -ni to redio, you get redioni = “on the radio.” So:
• napenda kusikiliza muziki redioni = “I like to listen to music on the radio.”
You can also simply say ninapenda kusikiliza redio = “I like listening to the radio.”

Yes. Swahili has a relative/temporal marker -po- meaning “when/while.” You insert it into the verb:
• ni- (I) + ‑na- (present) + ‑po- (when) + pika (cook) = ninapopika
So you can say:
Ninapenda kusikiliza muziki wa redio ninapopika.
This literally means “I like listening to radio music when I cook,” just like the original.