Short answers, pulled from the story.
The 2017, 2018 Russian protests were triggered by an investigative film titled He Is Not Dimon To You released by Alexei Navalny on YouTube in early 2017. Public anger also stemmed from poorly planned apartment demolitions in Moscow and ongoing truck driver strikes against the Platon toll system since 2015.
Anti-corruption rallies erupted simultaneously in more than 100 Russian towns and cities on the 26th of March 2017. Independent observers estimated that 60,000 people participated across 80 locations during these initial demonstrations.
Demonstrations took place in 154 towns and cities across the country with tens of thousands attending while authorities detained more than one thousand participants nationwide. A new wave of protests emerged on the 12th of June 2017 with even broader geographic reach.
The Central Election Commission refused to register Alexei Navalny as a presidential candidate in late January 2018 which triggered a Strike of Voters campaign urging supporters not to participate in upcoming elections. Protests occurred in 118 Russian cities on the 28th of January 2018 following this decision.
From July through September 2018, protests shifted focus toward opposing planned increases in retirement age. Almost every weekend saw demonstrations organized across nearly all major Russian cities including Novosibirsk and Krasnodar with total participation exceeding two hundred thousand people over several months.