Learn Farsi: من تازه درباره‌ی معماری مدرن خوانده‌ام. - I have just read about modern architecture.

As an adjective, تازه means "fresh" or "new" (like fresh bread). However, when used as an adverb before a verb—especially in the present perfect or simple past tense—it means "just" or "recently". Here, تازه ... خوانده‌ام means "I have just read".

Why is there a ‌ی added to the end of درباره (about)?

درباره (darbāre) is a preposition that requires an Ezafe to link it to the noun that follows it. Because the word ends in a silent 'h' (which acts as a vowel sound in Farsi), the connecting Ezafe must be written as ‌ی (ye) instead of just being an unwritten vowel sound.

How do we link معماری (architecture) and مدرن (modern) when speaking?

They are linked by a spoken Ezafe. Because in Farsi the noun comes before the adjective, you need the Ezafe to connect them. Since معماری ends in the vowel sound 'i', the connecting sound becomes a 'ye'. You will pronounce it as معماریِ مدرن (me'māri-ye modern), even though the Ezafe is not explicitly written here.

What tense is the verb خوانده‌ام and how is it built?