ばかり has a number of grammatical usages in Japanese, but one of the most common is with the simple past tense to express that an action has just taken place.
【Verb: Simple Past】ばかり
食べたばかり。
Just eaten.
映画が始まったばかり。
The film has just started.
仕事から帰ってきたばかりだから着替えてからご飯を作るね。
I’ve just returned home from work so I’ll make dinner after I’ve changed.
Despite having only just got his driving license, he seems to think he’s Schumacher.
Note: We will meet the “seems like” grammar later.
先週知り合ったばかりなのに昔からの友達のような感じがする。
To feel like old friends despite having only just met last week.
Modifying Nouns
Because ばかり functions grammatically like a noun, you must use the particle の to connect it to another noun (e.g., “A newly bought shirt” or “A newly built house”).
戦争が終わったばかりの頃には毎日の生活が苦しかった。
When the war had just finished (in the time just after the war), everyday life was difficult.
これは買ったばかりのカメラです。
This is a newly bought camera.
Conversational Pronunciation
This structure is heavily used in conversation, where very often a bridging っ will be inserted in the pronunciation to put emphasis on the か.