Download dmg file for installation. Disk image is automatically mounted on desktop. Normally you must have :
Drag Logfly icon into the Applications folder.
If you don't have this, you must search on the desktop screen for Logfly disk and double click inside.
When you launch Logfly at first time, you probably obtain a warning “Logfly is an application downloaded from the internet. Are you sure you want to open it ?”. You can can run it !!!
Updates :
For informations about updates, click on About in Logfly options
If a new version is available, the button "New version is available" is enabled
After downloading, drag Logfly icon and confirm the replacement.