Map terrain awareness, the right way to deliver units with transports, and why landing aircraft affects visibility.
BAR maps have height variation that matters for gameplay. Lava levels, cliff edges, and elevated positions all affect unit pathing and combat. Community reference charts exist that show height levels for specific maps. Study the ones you play most often so you know when terrain will block movement or give vision advantage.
The yellow ring you see when loading a transport is one delivery method. Another approach is setting the transport to guard a lab or factory. When set to guard, the transport automatically picks up produced units and delivers them to the rally point. Set it once and forget it.
Aircraft on the ground are detected using ground line of sight instead of air line of sight. Ground detection range is shorter. Landed aircraft also stay put instead of wandering, making them easier to shield with anti-air. They remain vulnerable to anti-fire but are harder to find in the first place.
[Crd] Before discovering Creed, I was thinking the only thing that separates BAR from the perfect RTS is a friendly and safe social environment for new players to learn and feel included.
Win with skill, teamwork, and respect.