From the superseding indictment:

Count 1: 18 U.S.C. § 371 (Conspiracy to Defraud the United States)
Count 2: 18 U.S.C. § 1512(k) (Conspiracy to Obstruct an Official Proceeding)
Count 3: 18 U.S.C. §§ 1512(c)(2), 2 (Obstruction of and Attempt to Obstruct an
Official Proceeding)
Count 4: 18 U.S.C. § 241 (Conspiracy Against Rights)

Read the full indictment here:
https://www.politico.com/f/?id=00000191-9582-d690-a9f3-dfff52f50000

If you read the elaboration of each count in the indictment, it provides the
details of the actual actions Trump did that comprise a violation of the law.

Jack Smith believes he can prove beyond a reasonable doubt that Trump committed
actions that violate those provisions of the U.S.C. Here what the indictment
says about manner and means for Count 1:

a. The Defendant and co-conspirators used knowingly false claims of election
fraud to get state legislators and election officials to subvert the
legitimate election results and change electoral votes for the Defendant's
opponent, Joseph R. Biden, Jr., to electoral votes for the Defendant. That
is, on the pretext of baseless fraud claims, the Defendant pushed
officials in certain states to ignore the popular vote; disenfranchise
millions of voters; dismiss legitimate electors; and ultimately, cause the
ascertainment of and voting by illegitimate electors in favor of the
Defendant.

b. The Defendant and co-conspirators organized fraudulent slates of electors
in seven targeted states (Arizona, Georgia, Michigan, Nevada, New Mexico,
Pennsylvania, and Wisconsin), attempting to mimic the procedures that the
legitimate electors were supposed to follow under the Constitution and
other federal and state laws. This included causing the fraudulent
electors to meet on the day appointed by federal law on which legitimate
electors were to gather and cast their votes; cast fraudulent votes for
the Defendant; and sign certificates falsely representing that they were
legitimate electors. Some fraudulent electors were tricked into
participating based on the understanding that their votes would be used
only if the Defendant succeeded in outcome-determinative lawsuits within
their state, which the Defendant never did. The Defendant and co-
conspirators then caused these fraudulent electors to transmit their false
certificates to the Vice President, in his capacity as President of the
Senate, and other government officials to be counted at the certification
proceeding on January 6.

c. The Defendant and co-conspirators attempted to enlist the Vice President,
in his ceremonial role as President of the Senate at the January 6
certification proceeding to fraudulently alter the election results.
First, using knowingly false claims of election fraud, the Defendant and
co conspirators attempted to convince the Vice President to use the
Defendant's fraudulent electors, reject legitimate electoral votes, or
send legitimate electoral votes to state legislatures for review rather
than counting them. When that failed, on the morning of January 6, the
Defendant and co-conspirators repeated knowingly false claims of election
fraud to gathered supporters, falsely told them that the Vice President
had the authority to and might alter the election results, and directed
them to the Capitol to obstruct the certification proceeding and exert
pressure on the Vice President to take the fraudulent actions he had
previously refused.

d. After it became public on the afternoon of January 6 that the Vice
President, as President of the Senate, would not fraudulently alter the
election results, a large and angry crowd-including many individuals whom
the Defendant had deceived into believing the Vice President could and
might change the election results-violently attacked the Capitol and
halted the proceeding. As violence ensued, the Defendant and co-
conspirators exploited the disruption by redoubling efforts to levy false
claims of election fraud and convince Members of Congress to further delay
the certification based on those claims.

Those are serious crimes, and Smith can prove that Trump committed them. Trump
needs to go to trial, be convicted and put in prison.