المطعم قريب، لكن ليس لدي وقت اليوم، والخبز في المطعم ليس جديدا لأن الخبز قديم.

Arabic often uses a nominal sentence (جملة اسمية) with no verb to be in the present tense.

• المطعم = the subject (the restaurant)
• قريب = the predicate (near)
  So المطعم قريب literally reads The restaurant (is) near.

Adjectives/predicates agree with the noun in gender (and number).

• المطعم is grammatically masculine, so the predicate is قريب (masc.).
  If the noun were feminine (e.g., المدرسة), you’d say المدرسة قريبة.

In fully-vowelled Arabic, you might see:

• المطعمُ قريبٌ (both words marked for case and indefiniteness)

In normal unvowelled writing, those endings are usually omitted, so you see قريب. Also, even when vowelled, المطعم is definite (has الـ), but قريب can still be indefinite as a predicate.

لكن means but / however and connects two ideas that contrast:

• المطعم قريب (The restaurant is near)
• لكن ليس لدي وقت اليوم (but I don’t have time today)

You may also see ولكن (and but) depending on style.

ليس is a negation word used to negate nominal-type statements (including “having” expressions like لدي).
Structure here is essentially:

• ليس
  • (something like “for me/with me”) + the thing

So ليس لدي وقت = I do not have time (literally: There is not (for me) time).

لدي means with/at me and is used to express possession in MSA (similar to عندي):

• لدي = لدى
  • ي (my / me) So ليس لدي وقت literally means There isn’t time with me, i.e., I don’t have time.

In Arabic, after possession/availability expressions like لدي/عندي, the noun is often indefinite when you mean “any/a” of something:

• ليس لدي وقت = I don’t have (any) time If you said ليس لدي الوقت, it would sound more like I don’t have the (specific) time, which is a different nuance.

اليوم means today and functions as a time adverb. It commonly comes after the thing it modifies:

• ليس لدي وقت اليوم = I don’t have time today Other placements can be possible for emphasis, but this is very natural.

في المطعم is a prepositional phrase meaning in the restaurant. It tells you where the bread is (or where the relevant bread is being talked about).
Word order is flexible; you could also say:

• والخبز ليس جديدًا في المطعم …but the given order keeps في المطعم close to الخبز to specify “the bread (that’s) in the restaurant.”

Because جديدًا is the predicate of ليس, and the predicate of ليس is typically accusative (منصوب). In unvowelled writing, the fatḥa-tanwīn (ً) is often shown with an extra alif at the end:

• جديدًا → often written جديدا

So ليس جديدًا = is not new.

After لأن (because), the clause الخبز قديم is a normal nominal sentence (no ليس), so:

• الخبز = subject (marfūʿ in grammar)
• قديم = predicate (also marfūʿ in grammar)

So you get قديم (not the accusative form used after ليس).
Also, you may see لأنّ (with a shadda) in formal writing; both point to the “because” connection in common MSA usage.