だけでJust by, Just with

だけで is a combination of the adverbial particle だけ, and the case marking particleで. This expression is regularly thought of as meaning 'just by (A), (B)'. However, the literal translation is a bit closer to 'with only (A), (B)'. This reflects the で particle's standard usage of showing a 'tool' that is being used to achieve a certain result.

To use だけで, simply attach it to the end of any (non ます) form of verb, or noun.

Fun Fact

だけ differs from しか in one very important way. だけ highlights that there is/was more than one option, but that only one thing was chosen/used. However, しか implies that there is only one possible option to begin with.