Questions & Answers about Ich kaufe langsam ein, weil ich nicht in Eile bin.
Because einkaufen is a separable-prefix verb. In a main clause the finite part (kaufe) appears in second position, and its prefix (ein) “splashes” off to the end.
Langsam is an adverb of manner. In German you normally put manner adverbs just before the separable prefix that sits at the end. The basic pattern here is Subject – Verb – (other elements) – lovely manner adverb – separable prefix.
Weil introduces a subordinate (dependent) clause in German. Standard punctuation rules say you must separate main and subordinate clauses with a comma.
In subordinate clauses introduced by weil, German uses verb-final word order. That means all verb forms (here bin) go to the end.