30 USD is very little to invest in several assets, the recommendation is to analyze and invest in a single currency when it drops....

I am new to the crypto world, I bought 30$ in more than 100 coins, over a month ago it had risen almost 20$ and now it has gone down again, I decided to put them in earn by a friend who recommended it to me. If anyone can recommend a strategy to multiply my cryptos, I will be grateful, I am open to suggestions.