If you see “[Locked Content]” next to an item, it is explained here.

Locked Content refers to content that can not be obtained through normal spawns and such. A primary example of this in my mod are ore nodes. Since ore nodes must be placed directly into a map to be mined, these are considered "Locked Content".
In other words, since "diamond ore" doesn't spawn on Washington, you can't mind diamonds for a drill. Thus, the Diamond drill is locked content.

Although this is the case, there are a few solutions.
1. If you are the owner of a server, you can add the ore nodes directly onto your map through map editor.
2. I work with another content creator who is a good friend of mine, who has taught me most of what I know. We together have created a brand new map from scratch, which will contain ALL locked content that my mod has.[Disclaimer: Since this is a custom map made for a specific server, there are some custom map text, builds, etc, made for the server. This can not be removed. If this does not bother you, you may use this map as you please.] https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2895431960
3. If you would like to try out my content as well as solution 2’s map without any hassle, you can join a server that I administrate on. It is the server in which I usually play on, and it will always be updated as soon as possible for any new content I add. It also has a lot of other fun mods. (If you do join the discord, feel free to say hi, and ping me in general chat saying you are coming from this page.)
Server Discord: https://discord.gg/rT5BuZayNF
IP: http://156.236.84.62/
Port: 27100

4. If you have economy/money on your server, you can simply add locked content items to the shop. You will most likely only need to add base material items.

Any map locked content will be displayed here, as well as on the main page with “[Locked Content]” in bold next to an item.