Lock/unlock: press both adjustment buttons at the same time
I maybe ought not venture even that much help. A simple
search offered that up expediently. Always useful to check out a manufacture's site. They often got things like product
manuals, FAQ pages. FAQ means Frequently Asked (and answered) Questions for anyone two days Internet/Web old.
I don't write that being nasty, derogatory to anyone. We all "just start out" at one time or another. I've also included another useful link. Check out the pretty highlighted word manuals above, it leads to Manuals Library, a site hosting manuals or quick access to manuals.
Also take note that Smok / SmokTech /Smok Tech likes to have "nifty" ways to lock and unlock devices. They don't usually cue anyone in, either. Be aware, too, Smok recently has gotten some heat for not being too forthcoming to help users with issues. Of course, not many manufactures offer too much help with anything nowadays.
Planned obsolesce along with other seemingly underhanded "marketing/sales" ploys have been subject to discussions on VU a while. Think my best advice still applies, praise in public, castigate in private. If it becomes a "commonly known" issue, then yes, bring it to light in public. Try to still be respectful. No point muddying waters already stirring.