1. Form and meaning
Use weil and da to explain a reason; obwohl introduces a contrast between an expectation and reality. These are subordinate conjunctions, so the conjugated verb goes to the end of that clause. Put a comma between the clauses.
When you study this pattern, identify its communicative purpose first. Then check the verb form, case and word order. German clauses are easier to control when you learn the connector together with the sentence pattern it requires.
Example 1: Ich bleibe zu Hause, weil ich krank bin.
Example 2: Obwohl es regnet, gehen wir spazieren.
2. How to use it accurately
Build your own sentence by replacing one part of the model while keeping the grammar pattern unchanged. Pay attention to the finite verb, commas, noun capitalisation and the case required by any preposition. Read the sentence aloud and compare the meaning with the English explanation.
Study strategy: Make one affirmative example, one question or contrast, and one sentence connected to your own life.