The 99% of investing resources on the internet seems to be US centric. How would I adapt the ideas I get from the to do investing in other countries? Say for eg, Germany or India.
It really depends on the type of advice. Be mindful of any particular limits, amounts, or rates in the advice, and consider whether these are specific to the U.S. rules/frameworks. Some types of advice, such as "invest in state or municipal bonds to take advantage of their tax-exempt status" would definitely be specific to U.S. tax laws and not necessarily applicable to other countries.
It's kind of obvious there are more English resources, because anyone trying to reach a broader audience will use English. These people will know the details in their specific region, which is why you get answer for PRIIPS etc here on this site as well.
However, most advice is anyhow universally applicable. For example, if you want to understand why passive investment is usually a good choice, what the return of bond ETFs looks like or learn details about an options theta has the same answer no matter where you live.
For short, if you have a specific question, I am almost certain google will find an answer to almost all your problems, especially for such a large and wealthy country like Germany where there are lots of resources as well.
If you have a specific example where you think it doesn't work, please add it to you question so that we can have a look if there is indeed nothing (I'd doubt here).