Young investors or the beginners in the mutual fund tend to have misconceptions to occupy their portfolio more with mid cap and small cap stocks or mutual funds. They assume that it will yield good returns over the long run. Needless to say, an investment initiated with assumptions without rigorous data support would end up with loss only.

So let's know the difference between large cap and small cap before you conclude a suitable investment ratio of both in your portfolio.

It is quite clear that small-cap indices have broadly shown a downward trend. One of the possibility could be that the small-cap may work good and turn out to be a multi-bagger. However, they may lose during the sideways movement or crash. Thus, it averages its poor performance.

On the contrary, Large-cap funds are those funds which invest their large portion in companies with large market capitalization. Thus it lowers the investor's risk, gets a steady return. The failure scope of the companies future is near to nil.
Thus I would suggest you manage your portfolio with the ratio of 10% small cap and rest with midcap and large cap funds.

Below is a link of an answer that helped me know the best small-cap and mid-cap fund to invest this year. Take a look: