German beginners have a question about clauses

The example sentence you gave above itself has a word order problem. It should be Wenn das Wetter sch?n ist, gehe ich spazieren.

The clause should use final word order or what is called coda word order. To put it simply, the (conjugated) verb is placed at the end of the clause;

When the clause is brought forward, it means that a certain component of the main clause is brought forward, so the main clause part Reverse order should be used (because there is a sentence element first and the verb in second position).

Happy study!