The explainer videos I have seen are wildly wrong. I learned this stuff by reading the Basel accords [2], working with banking regulators and central bankers, working on banks' capital reserve models etc. That is to say I know how this actually works because I have been inside the sausage-making process for good or ill - I didn't learn it second-hand from someone who probably also learned it second-hand which is the feel I get from these videos.
Almost any time you see someone "explain" fractional reserve banking it is about 99% probably total bullshit. It's got to the point where "fractional reserve" is almost a trigger phrase for me - I know when I hear it that it is highly likely the speaker doesn't know what they are talking about. Almost like when you hear the word "fiat currency" you know it's very likely someone is going to try to shill you some crypto. An explanation which is not nonsense is here. [3] Fractional reserve banking means the bank doesn't need to keep the full amount of deposits in reserve, but can use some percentage to make loans. These loans are assets the bank has, but as with the example I gave above where you lend to a friend, no additional money is created in this process and when a bank does it, it's not fundamentally any different.
[1] You can find the definitions of M1 and M2 money and a good explanation of what's included in the definition of "money" here https://www.investopedia.com/terms/m/moneysupply.asp
[2] Which are not secret by the way - you don't have to be initiated into the templars or something to understand them. They are boring as all hell to read but otherwise reasonably understandable with a little bit of background https://www.bis.org/basel_framework/
[3] https://www.investopedia.com/terms/f/fractionalreservebankin...