switch party is next to the tabs with the resources and buildings. (embark is the dungeon btw)
buildings need research(shrines: stand next to a shrine and enter it) and appear on the tab when its completly researched. After that you need to build it in the light green area(pacified area) and look at some errors
you want to basically equip mostly armor(protection) rest is for getting rat submission to 100% or throwing them at your enemies. for example -100% speech makes a rat bite completly useless. +100 arousal dildo can give you some strangely cracy vulnarability (pretty much kills any ability to disrupt incoming abilities)
you can use stuff on enemies in a fight like a leash (catches them) or bad equip just test it...
remember to let someone work in every building otherwise that building is useless even shrines.
you also need to embark to increase your pacified area. pick the very short lenght before to see the area you pacify.