Do not disable anything created by the LogShipping setup process.
You need to put the needed exclusions into your existing Transaction Log Backup process to ensure it excludes the databases which are part of log shipping.
If you use Ola's maintenance solution, it will do this for your automatically.
If you use anything else you need to tell that software or piece of code, to not backup any logs for your log shipped databases.
LSBackup, LSCopy and LSRestore jobs MUST be enabled, to ensure the right data is put into the log shipping tables.
But yes, you need to make sure that the secondary server has TCP 445 open to the primary server and that the share is accessible between servers etc, then restore the full, diff and any logs up to the current point in time (depending how frequent you backup the log you may want to disable the old tx backup job while LS is being setup), then setup log shipping, reconfigure any legacy backup jobs and you are done.
The only thing to additionally remember is to periodically run "sp_help_revlogin" on primary and sync that to secondary to make the login SIDs and PWDs all match otherwise you will end up with orphaned logins on failover.