OR, sorry but I am keeping it simple so using Dr Saab definitions:
Deen = System of Life = The Divinely Prescribed Way of Life. In a loose sense, ‘religion’ equals ‘mazhab’ i.e. individual efforts to please God with rituals. ‘Religion’ even with a capital R may scarcely come close in meaning to the term ‘Deen’.
Salaat = To follow closely, like a runner-up (Musalli) follows the winning horse (Saabiq) = To follow Divine Commands.
Aqimussallat = Establish the System that facilitates the following of Divine Commands.
Individually the salaat is knowing what Allah wants you to do and do it
Collectively, society functions under the Divine commands, councils gather the people and resolve issues etc
Both individual and collective duty to Allah.