After downloading jenkins's war package and putting it into tomcat, what should I do if I log in to the web page and ask for a user name and password?

downloaded jenkins"s war package
and put it in the tomcat webapps of a linux machine
then open the web page
first login user name and password
this machine has been used by someone else before jenkins
but should not conflict with mine
what to do?
find solutions on the Internet
found that the version seems to be different, so there are no related directories or files
my jenkins version number is
Jenkins ver.. 2.121.1

after the war package is unfolded, the first layer directory is
bootstrap help LogFileOutputStream.class META-INF
ColorFormatter.class images Main.class robots.txt
css JNLPMain.class MainDialog$1$1.class scripts
dc-license.txt jsbundles MainDialog$1.class. WEB-INF
executable LogFileOutputStream$1.class MainDialog.class winstone.jar
favicon.ico LogFileOutputStream$2.class Main$FileAndDescription.class

Mar.22,2021

check whether there is already something in the user directory ~ / .jenkins directory. Jenkins will install the program in this directory. There are two ways: 1. Delete the files in this directory, but this will make the version installed by others unavailable. 2. Create a new user and install jenkins under the new user

.
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b35e1e-2bfc2.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b35e1e-2bfc2.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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