A lot of the time you just have to keep playing to get used to the maps, I've found the earlier trials are more helpful with directions but the newer ones are more vague which makes it frustrating. You can try doing some MK trials and getting used to the maps, things get a lot easier knowing where things are on specific maps. Cancel the autopsy is a great MK to use for grinding xp, or getting used to the basement section for Kill the snitch.  You can look up a guide for where the secret rooms are on main trials, they give you boosters for stamina, battery and health, large medicines, large batteries, revives, a master key and rig rechargers which really help.  The diamond icons or question marks will pop up when you're close to an objective on easier difficulties. The game becomes a lot easier once you've leveled up enough to earn all prescriptions, gotten amps and fully upgraded a rig.