Insert logo png

hello everyone, i'm trying elgg, and after adding a few plug-ins i would need to replace the "site name" header with a png logo, but being an inexperienced programmer i don't want to modify something incorrectly and compromise the functioning of the whole site. can anyone tell me which files to modify and kindly post the code to insert? Thanks to anyone who can provide me with information on this matter.

Using elgg 6.1.1

Beginning Developers

Beginning Developers

This space is for newcomers, who wish to build a new plugin or to customize an existing one to their liking