You need to wipe your drive and reinstall windows in order to switch to the ltsc branch.
This said, are you aware that windows 10 dies in October and any security issues (~50 discovered every month, although not all very serious) won't get patched anymore?
Better get used now to w11 or Linux rather than next year after automatically getting a ransomware and losing all your data after visiting a dodgy site
Only if you install w10 1809 that was released in 2018. It is ancient and missing so many features that's almost using another operating system. But at least will get security updates until 2028
Otherwise they altered the deal, latest ltsc was released in 2021 with only 5 years of security updates