First things first, hello you there my dear reader! Hope you're having a good day.

You'll have to excuse me, but I'm not an english-native speaker (or a legalese-native speaker either) so please ignore my inevitable spelling mistakes.

Open Gaming License for Dummies

So here I am, doing my business as usual (that is designing small and niche indie ttrpgs), when I found myself scouring the interwebs for an old article about DnD 5e's SRD, aka the System Reference Document, aka the good old thing that let you have free snippets of rules from your beyond favorite website.

I recently read somewhere that Pathfinder 1e was able to make "its own 3.5e" by virtue of using only things within the confines of the SRD and that allowed for the game to be outside of danger of being copyright striked. So... how does this work exactly?

Notice that I'm not interested into making products for DM's guild directly, or DnD 5e products at all. I just want to make my own game (inspired by 5e in order for it to be easy to learn coming from that system) and possibly marketing it to the public later down the line, but it's the first time I'm not making something from the ground up and I don't really know how much leeway I have within the OGL.

These are my questions to the reddit hivemind:

• What can I use from the SRD? Can I take pieces of it (such as rules text or lore pieces) verbatim?
• What must/should I add in my future game product to make it sellable?
• Can I reference DnD 5e's rules/pages/game elements in my own rulebook (highlighting the differences for it to be easier to digest)?

Thank you for reading, I hope to get a clear answer! Have a nice day!