Lyman-alpha emitters (LAEs) provide a crucial window into the high-redshift universe, allowing us to trace star formation, probe the epoch of reionization, and map the circumgalactic medium (CGM). However, because Lyα is a resonant line, its photons are endlessly scattered by neutral hydrogen, making it inherently difficult to extract intrinsic physical properties from observed spectra and surface brightness profiles (SBPs). In this talk, I will present a multi-scale approach to decoding these complex radiative transfer effects. First, we explore the detailed physics of the CGM using an outflowing-halo Monte Carlo Radiative Transfer (MCRT) model. By applying this model to deep integral-field observations of 163 LAEs from MUSE at z=3-6, we demonstrate that simultaneously fitting both the Lyα spectrum and the SBP is absolutely essential to break severe parameter degeneracies. This modeling reveals that the spatial extent of Lyman-Alpha Halos (LAHs) is largely driven by the physical extents of the medium and the source, coupled with low expanding velocities at large radii, rather than solely by optical depth. Building on these physical insights, we then transition to the massive statistical power of the One-hundred-deg2 DECam Imaging in Narrowbands (ODIN) survey, which provides uniformly selected LAEs across multiple cosmic epochs. I will present our recent targeted search for Lyman-continuum (LyC) leaking galaxies among a pristine sample of 851 LAEs at z=4.5. Using deep CFHT u/u∗ band imaging, we identified 12 "gold" and 39 "silver" individual LyC leaker candidates. While stacking the full sample yields a non-detection--reflecting highly stochastic intergalactic medium transmission and intrinsic faintness--the robust individual candidates provide critical clues into the sources responsible for cosmic reionization, revealing tentative correlations between LyC leakage, UV continuum flux, and Lyα equivalent width. Finally, I will discuss our ongoing work on measuring LAHs around LAEs at z=2.4 and 3.1 using the ODIN narrowband survey. By combining large statistical samples with insights gained from radiative transfer modeling, this effort will help connect the observed properties of Lyα halos to the underlying distribution and kinematics of gas around galaxies.