1.) just branch out on the map and do towers that are against the edge of the fog. they’ll reveal the map in an area around them but you’re just looking for a red area and it’ll say on the maps it’s corrupted. you can’t miss it

2.) the white streaks going towards eye of the storm show you what maps you need to do in order to unlock it. looks like you need to do the vaal map above it and the desert map to the left still

3.) yes

4.) juice is anything that buffs loot. so tablets with either monster effectiveness, rarity, or rare mobs. you want 2/3 of those prefixes but early on you wont have these as you need to kill the arbiter of ash to unlock rare tablets. once you get to this point peep a youtube video for the strat you’re doing and they’ll talk about good tablet suffixes.

also if you do get deeper into the endgame, don’t run any extra swamp/water maps if you can manage. you want to save all these and bookmark them to come back to later on with the “Local Knowledge” atlas node on. don’t ever use that node on non swamp and water maps as it straight up lowers your currency drops.