How to actually coordinate 4 (for example) Scrum Teams in one common Sprint in Large-Scale Scrum (LeSS), all delivering a common Potentially Shippable Product Increment? As the co-creator of LeSS, I have been helping teams do this for many years.
In this 1-week LeSS mini-Sprint I serve as the LeSS coach and ScrumMaster and facilitate all events, with up to 4 teams (always at least 2 teams). Observers (such as other ScrumMasters) are welcome to attend all LeSS events, such as Sprint Planning in LeSS, Product Backlog Refinement in LeSS, and so forth, to learn how to apply Scrum at Scale.
Also during the week I introduce/coach many concrete techniques: specification by example, impact maps, wide-band delphi, agile modeling, Monte Carlo Simulation, acceptance-TDD, pomodoro, and more.
A product group, including the Teams, adopting LeSS