It seems that some Americans say that the Reagan administration brought about the collapse of the Soviet Union. What action is the US supposed to have taken that brought about this collapse, a collapse so long wished but not found in the decades before?

This seems to be the Standard Version:

’A central instrument for putting pressure on the Soviet Union was Reagan’s massive defense build-up, which raised defense spending from $134 billion in 1980 to $253 billion in 1989. This raised American defense spending to 7 percent of GDP, dramatically increasing the federal deficit. Yet in its efforts to keep up with the American defense build-up, the Soviet Union was compelled in the first half of the 1980s to raise the share of its defense spending from 22 percent to 27 percent of GDP, while it froze the production of civilian goods at 1980 levels.

Reagan’s most controversial defense initiative was SDI, the visionary project to create an anti-missile defense system that would remove the nuclear sword of Damocles from America’s homeland. Experts still disagree about the long-term feasibility of missile defense, some comparing it in substance to the Hollywood sci-fi blockbuster Star Wars. But the SDI’s main effect was to demonstrate U. S. technological superiority over the Soviet Union and its ability to expand the arms race into space. This helped convince the Soviet leadership under Gorbachev to throw in the towel and bid for a de-escalation of the arms race.

Particularly effective, though with unintended long-term side effects, was the Reagan administration’s support for the mujahideen (holy warriors) that were fighting against the Soviet forces in Afghanistan. Reagan was determined to make Afghanistan the Soviet Vietnam. Therefore in 1986 he decided to provide the mujahideen with portable surface-to-air Stinger missiles, which proved devastatingly effective in increasing Soviet air losses (particularly helicopters). The war in Afghanistan cost the United States about $1 billion per annum in aid to the mujahideen; it cost the Soviet Union eight times as much, helping bankrupt its economy.

Apart from his defense policies, Reagan also weakened the Soviet Union through economic moves. His supporters’ claims that he brought about the fall of the Soviet Union are somewhat weakened by the fact that he ended Carter’s grain embargo, which had produced alarming food shortages in the Soviet Union. On the other hand Reagan was able to reduce the flow of Western technology to the Soviet Union, as well to limit Soviet natural gas exports to Western Europe. One of the most effective ways in which his economic policies weakened the Soviet Union was by helping bring about a drastic fall in the price of oil in the 1980s, thereby denying the Soviet Union large inflows of hard currency".’
wais.stanford.edu

Of course it means that Reagan also set up al Qaeda, and the US's chronic indebtedness.

Well yeah Fred, Reagan told Gorbachev to take down the wall... remember? And then he did.

Simple as that right?

Yeah,Reagan's policies essentially bankrupted the Soviet Union. The ruble tanked, and many countries wanted to be paid in gold.