If you're looking to Download L on your Chromebook laptop Then read the following guideline.

The L-DART app is available to the general public for anyone with a Withings account. It is also linked to the study “Light-Dark and Activity Rhythm Therapy for sleep: Feasibility and acceptability in Schizophrenia spectrum disorders” (L-DART FitSz). You will need a Withings account to use it. It connects to the Withings server, using your Withings account, and displays your activity data (steps and sleep) from your activity tracking wearable, as a graph / plot. This enables you to compare your activity patterns over a period of days, weeks and months and keep track of when you are active and still. The app was developed by the Mobile Development Service in Research IT at The University of Manchester, based on a design by Sophie Faulkner, with input from patient public contributors.